diff --git a/app/controllers/Clas.scala b/app/controllers/Clas.scala
index e93b29b58f..370992f119 100644
--- a/app/controllers/Clas.scala
+++ b/app/controllers/Clas.scala
@@ -16,10 +16,8 @@ final class Clas(
       case _ if getBool("home") => renderHome
       case None                 => renderHome
       case Some(me) if isGranted(_.Teacher) =>
-        WithTeacher(me) { t =>
-          env.clas.api.clas.of(t.teacher) map { classes =>
-            Ok(views.html.clas.clas.teacherIndex(classes))
-          }
+        env.clas.api.clas.of(me) map { classes =>
+          Ok(views.html.clas.clas.teacherIndex(classes))
         }
       case Some(me) =>
         env.clas.api.student.isStudent(me.id) flatMap {
@@ -44,17 +42,15 @@ final class Clas(
   }
 
   def create = SecureBody(_.Teacher) { implicit ctx => me =>
-    WithTeacher(me) { t =>
-      env.clas.forms.clas.create
-        .bindFromRequest()(ctx.body)
-        .fold(
-          err => BadRequest(html.clas.clas.create(err)).fuccess,
-          data =>
-            env.clas.api.clas.create(data, t.teacher) map { clas =>
-              Redirect(routes.Clas.show(clas.id.value))
-            }
-        )
-    }
+    env.clas.forms.clas.create
+      .bindFromRequest()(ctx.body)
+      .fold(
+        err => BadRequest(html.clas.clas.create(err)).fuccess,
+        data =>
+          env.clas.api.clas.create(data, me) map { clas =>
+            Redirect(routes.Clas.show(clas.id.value))
+          }
+      )
   }
 
   private def preloadStudentUsers(students: List[lila.clas.Student.WithUser]): Unit =
@@ -62,14 +58,14 @@ final class Clas(
 
   def show(id: String) = Auth { implicit ctx => me =>
     WithClassAny(id, me)(
-      forTeacher = WithClass(me, id) { _ => clas =>
+      forTeacher = WithClass(me, id) { clas =>
         env.clas.api.student.activeWithUsers(clas) map { students =>
           preloadStudentUsers(students)
           views.html.clas.teacherDashboard.overview(clas, students)
         }
       },
       forStudent = (clas, students) =>
-        env.clas.api.teacher.of(clas) map { teachers =>
+        env.clas.api.clas.teachers(clas) map { teachers =>
           preloadStudentUsers(students)
           val wall = scalatags.Text.all.raw(env.clas.markup(clas.wall))
           Ok(views.html.clas.studentDashboard(clas, wall, teachers, students))
@@ -95,7 +91,7 @@ final class Clas(
 
   def wall(id: String) = Secure(_.Teacher) { implicit ctx => me =>
     WithClassAny(id, me)(
-      forTeacher = WithClass(me, id) { _ => clas =>
+      forTeacher = WithClass(me, id) { clas =>
         env.clas.api.student.allWithUsers(clas) map { students =>
           val wall = scalatags.Text.all.raw(env.clas.markup(clas.wall))
           views.html.clas.wall.show(clas, wall, students)
@@ -106,7 +102,7 @@ final class Clas(
   }
 
   def wallEdit(id: String) = Secure(_.Teacher) { implicit ctx => me =>
-    WithClass(me, id) { _ => clas =>
+    WithClass(me, id) { clas =>
       env.clas.api.student.activeWithUsers(clas) map { students =>
         Ok(html.clas.wall.edit(clas, students, env.clas.forms.clas.wall fill clas.wall))
       }
@@ -114,7 +110,7 @@ final class Clas(
   }
 
   def wallUpdate(id: String) = SecureBody(_.Teacher) { implicit ctx => me =>
-    WithClass(me, id) { _ => clas =>
+    WithClass(me, id) { clas =>
       env.clas.forms.clas.wall
         .bindFromRequest()(ctx.body)
         .fold(
@@ -130,7 +126,7 @@ final class Clas(
   }
 
   def notifyStudents(id: String) = Secure(_.Teacher) { implicit ctx => me =>
-    WithClass(me, id) { _ => clas =>
+    WithClass(me, id) { clas =>
       env.clas.api.student.activeWithUsers(clas) map { students =>
         Ok(html.clas.clas.notify(clas, students, env.clas.forms.clas.notifyText))
       }
@@ -138,7 +134,7 @@ final class Clas(
   }
 
   def notifyPost(id: String) = SecureBody(_.Teacher) { implicit ctx => me =>
-    WithClass(me, id) { _ => clas =>
+    WithClass(me, id) { clas =>
       env.clas.forms.clas.notifyText
         .bindFromRequest()(ctx.body)
         .fold(
@@ -158,7 +154,7 @@ final class Clas(
   }
 
   def archived(id: String) = Secure(_.Teacher) { implicit ctx => me =>
-    WithClass(me, id) { _ => clas =>
+    WithClass(me, id) { clas =>
       env.clas.api.student.allWithUsers(clas) map { students =>
         views.html.clas.teacherDashboard.archived(clas, students)
       }
@@ -167,7 +163,7 @@ final class Clas(
 
   def progress(id: String, key: String, days: Int) = Secure(_.Teacher) { implicit ctx => me =>
     lila.rating.PerfType(key) ?? { perfType =>
-      WithClass(me, id) { _ => clas =>
+      WithClass(me, id) { clas =>
         env.clas.api.student.activeWithUsers(clas) flatMap { students =>
           env.clas.progressApi(perfType, days, students) map { progress =>
             views.html.clas.teacherDashboard.progress(clas, students, progress)
@@ -178,7 +174,7 @@ final class Clas(
   }
 
   def edit(id: String) = Secure(_.Teacher) { implicit ctx => me =>
-    WithClass(me, id) { _ => clas =>
+    WithClass(me, id) { clas =>
       env.clas.api.student.activeWithUsers(clas) map { students =>
         Ok(html.clas.clas.edit(clas, students, env.clas.forms.clas.edit(clas)))
       }
@@ -186,7 +182,7 @@ final class Clas(
   }
 
   def update(id: String) = SecureBody(_.Teacher) { implicit ctx => me =>
-    WithClass(me, id) { _ => clas =>
+    WithClass(me, id) { clas =>
       env.clas.forms.clas
         .edit(clas)
         .bindFromRequest()(ctx.body)
@@ -204,8 +200,8 @@ final class Clas(
   }
 
   def archive(id: String, v: Boolean) = SecureBody(_.Teacher) { _ => me =>
-    WithClass(me, id) { t => clas =>
-      env.clas.api.clas.archive(clas, t.teacher, v) inject
+    WithClass(me, id) { clas =>
+      env.clas.api.clas.archive(clas, me, v) inject
         Redirect(routes.Clas.show(clas.id.value)).flashSuccess
     }
   }
@@ -214,7 +210,7 @@ final class Clas(
     if (getBool("gen")) env.clas.nameGenerator() map {
       Ok(_)
     } else
-      WithClassAndStudents(me, id) { _ => (clas, students) =>
+      WithClassAndStudents(me, id) { (clas, students) =>
         ctx.req.flash.get("created").map(_ split ' ').?? {
           case Array(userId, password) =>
             env.clas.api.student
@@ -240,7 +236,7 @@ final class Clas(
   def studentCreate(id: String) = SecureBody(_.Teacher) { implicit ctx => me =>
     NoTor {
       Firewall {
-        WithClassAndStudents(me, id) { t => (clas, students) =>
+        WithClassAndStudents(me, id) { (clas, students) =>
           env.clas.forms.student.create
             .bindFromRequest()(ctx.body)
             .fold(
@@ -254,7 +250,7 @@ final class Clas(
                   )
                 ).fuccess,
               data =>
-                env.clas.api.student.create(clas, data, t) map {
+                env.clas.api.student.create(clas, data, me) map {
                   case (user, password) =>
                     Redirect(routes.Clas.studentForm(clas.id.value))
                       .flashing("created" -> s"${user.id} ${password.value}")
@@ -266,7 +262,7 @@ final class Clas(
   }
 
   def studentInvite(id: String) = SecureBody(_.Teacher) { implicit ctx => me =>
-    WithClassAndStudents(me, id) { t => (clas, students) =>
+    WithClassAndStudents(me, id) { (clas, students) =>
       env.clas.forms.student
         .invite(clas)
         .bindFromRequest()(ctx.body)
@@ -283,7 +279,7 @@ final class Clas(
           data =>
             env.user.repo named data.username flatMap {
               _ ?? { user =>
-                env.clas.api.student.invite(clas, user, data.realName, t) map { so =>
+                env.clas.api.student.invite(clas, user, data.realName, me) map { so =>
                   Redirect(routes.Clas.studentForm(clas.id.value)).flashing {
                     so.fold("warning" -> s"${user.username} is already in the class") { s =>
                       "success" -> s"${user.username} (${s.realName}) has been invited"
@@ -297,7 +293,7 @@ final class Clas(
   }
 
   def studentShow(id: String, username: String) = Secure(_.Teacher) { implicit ctx => me =>
-    WithClassAndStudents(me, id) { _ => (clas, students) =>
+    WithClassAndStudents(me, id) { (clas, students) =>
       WithStudent(clas, username) { s =>
         env.activity.read.recent(s.user, 14) map { activity =>
           views.html.clas.student.show(clas, students, s, activity)
@@ -307,7 +303,7 @@ final class Clas(
   }
 
   def studentEdit(id: String, username: String) = Secure(_.Teacher) { implicit ctx => me =>
-    WithClassAndStudents(me, id) { _ => (clas, students) =>
+    WithClassAndStudents(me, id) { (clas, students) =>
       WithStudent(clas, username) { s =>
         Ok(views.html.clas.student.edit(clas, students, s, env.clas.forms.student edit s.student)).fuccess
       }
@@ -315,7 +311,7 @@ final class Clas(
   }
 
   def studentUpdate(id: String, username: String) = SecureBody(_.Teacher) { implicit ctx => me =>
-    WithClassAndStudents(me, id) { _ => (clas, students) =>
+    WithClassAndStudents(me, id) { (clas, students) =>
       WithStudent(clas, username) { s =>
         env.clas.forms.student
           .edit(s.student)
@@ -332,16 +328,16 @@ final class Clas(
   }
 
   def studentArchive(id: String, username: String, v: Boolean) = Secure(_.Teacher) { _ => me =>
-    WithClass(me, id) { t => clas =>
+    WithClass(me, id) { clas =>
       WithStudent(clas, username) { s =>
-        env.clas.api.student.archive(s.student, t.teacher, v) inject
+        env.clas.api.student.archive(s.student, me, v) inject
           Redirect(routes.Clas.studentShow(clas.id.value, username)).flashSuccess
       }
     }
   }
 
   def studentSetKid(id: String, username: String, v: Boolean) = Secure(_.Teacher) { _ => me =>
-    WithClass(me, id) { _ => clas =>
+    WithClass(me, id) { clas =>
       WithStudent(clas, username) { s =>
         (s.student.managed ?? env.user.repo.setKid(s.user, v)) inject
           Redirect(routes.Clas.studentShow(clas.id.value, username)).flashSuccess
@@ -350,7 +346,7 @@ final class Clas(
   }
 
   def studentResetPassword(id: String, username: String) = Secure(_.Teacher) { _ => me =>
-    WithClass(me, id) { _ => clas =>
+    WithClass(me, id) { clas =>
       WithStudent(clas, username) { s =>
         env.security.store.closeAllSessionsOf(s.user.id) >>
           env.clas.api.student.resetPassword(s.student) map { password =>
@@ -362,7 +358,7 @@ final class Clas(
   }
 
   def studentRelease(id: String, username: String) = Secure(_.Teacher) { implicit ctx => me =>
-    WithClassAndStudents(me, id) { _ => (clas, students) =>
+    WithClassAndStudents(me, id) { (clas, students) =>
       WithStudent(clas, username) { s =>
         if (s.student.managed)
           Ok(views.html.clas.student.release(clas, students, s, env.clas.forms.student.release)).fuccess
@@ -373,7 +369,7 @@ final class Clas(
   }
 
   def studentReleasePost(id: String, username: String) = SecureBody(_.Teacher) { implicit ctx => me =>
-    WithClassAndStudents(me, id) { _ => (clas, students) =>
+    WithClassAndStudents(me, id) { (clas, students) =>
       WithStudent(clas, username) { s =>
         if (s.student.managed)
           env.security.forms.preloadEmailDns(ctx.body) >> env.clas.forms.student.release
@@ -403,27 +399,16 @@ final class Clas(
     Redirect("https://forms.gle/b19pDZZuotncxtbRA")
   }
 
-  private def WithTeacher(me: lila.user.User)(
-      f: lila.clas.Teacher.WithUser => Fu[Result]
-  ): Fu[Result] =
-    env.clas.api.teacher withOrCreate me flatMap f
-
   private def WithClass(me: lila.user.User, clasId: String)(
-      f: lila.clas.Teacher.WithUser => lila.clas.Clas => Fu[Result]
+      f: lila.clas.Clas => Fu[Result]
   ): Fu[Result] =
-    WithTeacher(me) { t =>
-      env.clas.api.clas.getAndView(lila.clas.Clas.Id(clasId), t.teacher) flatMap {
-        _ ?? f(t)
-      }
-    }
+    env.clas.api.clas.getAndView(lila.clas.Clas.Id(clasId), me) flatMap { _ ?? f }
 
   private def WithClassAndStudents(me: lila.user.User, clasId: String)(
-      f: lila.clas.Teacher.WithUser => (lila.clas.Clas, List[lila.clas.Student]) => Fu[Result]
+      f: (lila.clas.Clas, List[lila.clas.Student]) => Fu[Result]
   ): Fu[Result] =
-    WithClass(me, clasId) { t => c =>
-      env.clas.api.student.activeOf(c) flatMap { students =>
-        f(t)(c, students)
-      }
+    WithClass(me, clasId) { c =>
+      env.clas.api.student.activeOf(c) flatMap { f(c, _) }
     }
 
   private def WithStudent(clas: lila.clas.Clas, username: String)(
@@ -431,9 +416,7 @@ final class Clas(
   ): Fu[Result] =
     env.user.repo named username flatMap {
       _ ?? { user =>
-        env.clas.api.student.get(clas, user) flatMap {
-          _ ?? f
-        }
+        env.clas.api.student.get(clas, user) flatMap { _ ?? f }
       }
     }
 }
diff --git a/app/views/clas/bits.scala b/app/views/clas/bits.scala
index 4e94c4651b..a4cf2b8a4e 100644
--- a/app/views/clas/bits.scala
+++ b/app/views/clas/bits.scala
@@ -50,7 +50,7 @@ private object bits {
 
   def showArchived(archived: Clas.Recorded)(implicit ctx: Context) =
     div(
-      trans.clas.closedByX(userIdLink(archived.by.value.some)),
+      trans.clas.closedByX(userIdLink(archived.by.some)),
       " ",
       momentFromNowOnce(archived.at)
     )
diff --git a/app/views/clas/clas.scala b/app/views/clas/clas.scala
index 1a4bc1e4b5..1e03d288e2 100644
--- a/app/views/clas/clas.scala
+++ b/app/views/clas/clas.scala
@@ -84,7 +84,7 @@ object clas {
   def teachers(clas: Clas)(implicit lang: Lang) =
     div(cls := "clas-teachers")(
       trans.clas.teachersX(
-        fragList(clas.teachers.toList.map(t => userIdLink(t.value.some)))
+        fragList(clas.teachers.toList.map(t => userIdLink(t.some)))
       )
     )
 
diff --git a/app/views/clas/student.scala b/app/views/clas/student.scala
index 179e9c5d80..a5c64de112 100644
--- a/app/views/clas/student.scala
+++ b/app/views/clas/student.scala
@@ -79,7 +79,7 @@ object student {
         p(
           trans.clas.invitedToXByY(
             a(href := routes.Clas.show(clas.id.value))(clas.name),
-            userIdLink(s.student.created.by.value.some, withOnline = false)
+            userIdLink(s.student.created.by.some, withOnline = false)
           ),
           " ",
           momentFromNowOnce(s.student.created.at)
diff --git a/app/views/clas/studentDashboard.scala b/app/views/clas/studentDashboard.scala
index bbc6afc484..6fad3932ba 100644
--- a/app/views/clas/studentDashboard.scala
+++ b/app/views/clas/studentDashboard.scala
@@ -4,8 +4,9 @@ import controllers.routes
 import lila.api.Context
 import lila.app.templating.Environment._
 import lila.app.ui.ScalatagsTemplate._
-import lila.clas.{ Clas, Student, Teacher }
+import lila.clas.{ Clas, Student }
 import lila.common.String.html.richText
+import lila.user.User
 
 object studentDashboard {
 
@@ -14,7 +15,7 @@ object studentDashboard {
   def apply(
       c: Clas,
       wall: Frag,
-      teachers: List[Teacher.WithUser],
+      teachers: List[User],
       students: List[Student.WithUser]
   )(implicit ctx: Context) =
     bits.layout(c.name, Left(c withStudents Nil))(
@@ -37,26 +38,25 @@ object studentDashboard {
           )
         ),
         tbody(
-          teachers.map {
-            case Teacher.WithUser(_, user) =>
-              tr(
-                td(
-                  userLink(
-                    user,
-                    name = span(
-                      strong(user.username),
-                      user.profile.flatMap(_.nonEmptyRealName) map { em(_) }
-                    ).some,
-                    withTitle = false
-                  )
-                ),
-                td(
-                  user.seenAt.map { seen =>
-                    trans.lastSeenActive(momentFromNow(seen))
-                  }
-                ),
-                challengeTd(user)
-              )
+          teachers.map { user =>
+            tr(
+              td(
+                userLink(
+                  user,
+                  name = span(
+                    strong(user.username),
+                    user.profile.flatMap(_.nonEmptyRealName) map { em(_) }
+                  ).some,
+                  withTitle = false
+                )
+              ),
+              td(
+                user.seenAt.map { seen =>
+                  trans.lastSeenActive(momentFromNow(seen))
+                }
+              ),
+              challengeTd(user)
+            )
           }
         )
       ),
diff --git a/modules/clas/src/main/BsonHandlers.scala b/modules/clas/src/main/BsonHandlers.scala
index 4bdee0e534..e56ff4ddeb 100644
--- a/modules/clas/src/main/BsonHandlers.scala
+++ b/modules/clas/src/main/BsonHandlers.scala
@@ -5,9 +5,6 @@ import reactivemongo.api.bson._
 
 private[clas] object BsonHandlers {
 
-  implicit val teacherIdBSONHandler = stringAnyValHandler[Teacher.Id](_.value, Teacher.Id.apply)
-  implicit val teacherBSONHandler   = Macros.handler[Teacher]
-
   import Clas.Recorded
   implicit val recordedBSONHandler = Macros.handler[Recorded]
 
diff --git a/modules/clas/src/main/Clas.scala b/modules/clas/src/main/Clas.scala
index e87d4628a2..ba4ca6a118 100644
--- a/modules/clas/src/main/Clas.scala
+++ b/modules/clas/src/main/Clas.scala
@@ -3,12 +3,14 @@ package lila.clas
 import scalaz.NonEmptyList
 import org.joda.time.DateTime
 
+import lila.user.User
+
 case class Clas(
     _id: Clas.Id,
     name: String,
     desc: String,
     wall: String = "",
-    teachers: NonEmptyList[Teacher.Id], // first is owner
+    teachers: NonEmptyList[User.ID], // first is owner
     created: Clas.Recorded,
     viewedAt: DateTime,
     archived: Option[Clas.Recorded]
@@ -24,7 +26,7 @@ case class Clas(
 
 object Clas {
 
-  def make(teacher: Teacher, name: String, desc: String) = Clas(
+  def make(teacher: User, name: String, desc: String) = Clas(
     _id = Id(scala.util.Random.alphanumeric take 8 mkString),
     name = name,
     desc = desc,
@@ -38,15 +40,7 @@ object Clas {
 
   case class Id(value: String) extends AnyVal with StringValue
 
-  case class Recorded(by: Teacher.Id, at: DateTime)
+  case class Recorded(by: User.ID, at: DateTime)
 
   case class WithStudents(clas: Clas, students: List[Student])
-
-  // case class WithAll(
-  //     clas: Clas,
-  //     teachers: List[Teacher],
-  //     students: List[Student]
-  // ) {
-  //   def userIds = teachers.map(_.userId) ::: students.map(_.userId)
-  // }
 }
diff --git a/modules/clas/src/main/ClasApi.scala b/modules/clas/src/main/ClasApi.scala
index 4815862e40..6316aad9ad 100644
--- a/modules/clas/src/main/ClasApi.scala
+++ b/modules/clas/src/main/ClasApi.scala
@@ -23,39 +23,13 @@ final class ClasApi(
 
   import BsonHandlers._
 
-  object teacher {
-
-    val coll = colls.teacher
-
-    def withOrCreate(user: User): Fu[Teacher.WithUser] =
-      coll.byId[Teacher](user.id) flatMap {
-        case Some(teacher) => fuccess(Teacher.WithUser(teacher, user))
-        case None =>
-          val teacher = Teacher make user
-          coll.insert.one(teacher) inject Teacher.WithUser(teacher, user)
-      }
-
-    def of(clas: Clas): Fu[List[Teacher.WithUser]] =
-      coll.ext.byOrderedIds[Teacher, Teacher.Id](clas.teachers.toList)(_.id) flatMap withUsers
-
-    def withUsers(teachers: List[Teacher]): Fu[List[Teacher.WithUser]] =
-      userRepo.coll.idsMap[User, User.ID](
-        teachers.map(_.userId),
-        ReadPreference.secondaryPreferred
-      )(_.id) map { users =>
-        teachers.flatMap { s =>
-          users.get(s.userId) map { Teacher.WithUser(s, _) }
-        }
-      }
-  }
-
   object clas {
 
     val coll = colls.clas
 
     def byId(id: Clas.Id) = coll.byId[Clas](id.value)
 
-    def of(teacher: Teacher): Fu[List[Clas]] =
+    def of(teacher: User): Fu[List[Clas]] =
       coll.ext
         .find($doc("teachers" -> teacher.id))
         .sort($doc("archived" -> 1, "viewedAt" -> -1))
@@ -67,16 +41,16 @@ final class ClasApi(
         .sort($sort desc "createdAt")
         .list[Clas]()
 
-    def create(data: ClasForm.ClasData, teacher: Teacher): Fu[Clas] = {
+    def create(data: ClasForm.ClasData, teacher: User): Fu[Clas] = {
       val clas = Clas.make(teacher, data.name, data.desc)
       coll.insert.one(clas) inject clas
     }
 
     def update(from: Clas, data: ClasForm.ClasData): Fu[Clas] = {
       val clas = data update from
-      userRepo.filterByRole(clas.teachers.toList.map(_.value), Permission.Teacher.dbKey) flatMap { filtered =>
+      userRepo.filterByRole(clas.teachers.toList, Permission.Teacher.dbKey) flatMap { filtered =>
         val checked = clas.copy(
-          teachers = clas.teachers.toList.filter(t => filtered(t.value)).toNel | from.teachers
+          teachers = clas.teachers.toList.filter(filtered.contains).toNel | from.teachers
         )
         coll.update.one($id(clas.id), checked) inject checked
       }
@@ -85,7 +59,7 @@ final class ClasApi(
     def updateWall(clas: Clas, text: String): Funit =
       coll.updateField($id(clas.id), "wall", text).void
 
-    def getAndView(id: Clas.Id, teacher: Teacher): Fu[Option[Clas]] =
+    def getAndView(id: Clas.Id, teacher: User): Fu[Option[Clas]] =
       coll.ext
         .findAndUpdate[Clas](
           selector = $id(id) ++ $doc("teachers" -> teacher.id),
@@ -93,6 +67,9 @@ final class ClasApi(
           fetchNewObject = true
         )
 
+    def teachers(clas: Clas): Fu[List[User]] =
+      userRepo.byOrderedIds(clas.teachers.toList, ReadPreference.secondaryPreferred)
+
     def isTeacherOf(teacher: User, clasId: Clas.Id): Fu[Boolean] =
       coll.exists($id(clasId) ++ $doc("teachers" -> teacher.id))
 
@@ -102,7 +79,7 @@ final class ClasApi(
           coll.exists($inIds(clasIds) ++ $doc("teachers" -> teacherId))
         }
 
-    def archive(c: Clas, t: Teacher, v: Boolean): Funit =
+    def archive(c: Clas, t: User, v: Boolean): Funit =
       coll.update
         .one(
           $id(c.id),
@@ -168,11 +145,11 @@ final class ClasApi(
     def create(
         clas: Clas,
         data: ClasForm.NewStudent,
-        teacher: Teacher.WithUser
+        teacher: User
     ): Fu[(User, ClearPassword)] = {
       val email    = EmailAddress(s"noreply.class.${clas.id}.${data.username}@lichess.org")
       val password = Student.password.generate
-      lila.mon.clas.studentCreate(teacher.user.id)
+      lila.mon.clas.studentCreate(teacher.id)
       userRepo
         .create(
           username = data.username,
@@ -181,25 +158,25 @@ final class ClasApi(
           blind = false,
           mobileApiVersion = none,
           mustConfirmEmail = false,
-          lang = teacher.user.lang
+          lang = teacher.lang
         )
         .orFail(s"No user could be created for ${data.username}")
         .flatMap { user =>
           userRepo.setKid(user, true) >>
             userRepo.setManagedUserInitialPerfs(user.id) >>
-            coll.insert.one(Student.make(user, clas, teacher.teacher.id, data.realName, managed = true)) >>
+            coll.insert.one(Student.make(user, clas, teacher.id, data.realName, managed = true)) >>
             sendWelcomeMessage(teacher, user, clas) inject
             (user -> password)
         }
     }
 
-    def invite(clas: Clas, user: User, realName: String, teacher: Teacher.WithUser): Fu[Option[Student]] = {
-      lila.mon.clas.studentInvite(teacher.user.id)
-      val student = Student.make(user, clas, teacher.teacher.id, realName, managed = false)
+    def invite(clas: Clas, user: User, realName: String, teacher: User): Fu[Option[Student]] = {
+      lila.mon.clas.studentInvite(teacher.id)
+      val student = Student.make(user, clas, teacher.id, realName, managed = false)
       coll.insert.one(student) >> sendWelcomeMessage(teacher, user, clas) inject student.some
     }.recover(lila.db.recoverDuplicateKey(_ => none))
 
-    private[ClasApi] def join(clas: Clas, user: User, teacherId: Teacher.Id): Fu[Student] = {
+    private[ClasApi] def join(clas: Clas, user: User, teacherId: User.ID): Fu[Student] = {
       val student = Student.make(user, clas, teacherId, "", managed = false)
       coll.insert.one(student) inject student
     }
@@ -209,7 +186,7 @@ final class ClasApi(
       authenticator.setPassword(s.userId, password) inject password
     }
 
-    def archive(s: Student, t: Teacher, v: Boolean): Funit =
+    def archive(s: Student, t: User, v: Boolean): Funit =
       coll.update
         .one(
           $id(s.id),
@@ -229,10 +206,10 @@ final class ClasApi(
         }
     }
 
-    private def sendWelcomeMessage(teacher: Teacher.WithUser, student: User, clas: Clas): Funit =
+    private def sendWelcomeMessage(teacher: User, student: User, clas: Clas): Funit =
       msgApi
         .post(
-          orig = teacher.user.id,
+          orig = teacher.id,
           dest = student.id,
           text = s"""${lila.i18n.I18nKeys.clas.welcomeToClass
             .txt(clas.name)(student.realLang | lila.i18n.defaultLang)}
diff --git a/modules/clas/src/main/ClasForm.scala b/modules/clas/src/main/ClasForm.scala
index 46229f408b..15d5d04c0e 100644
--- a/modules/clas/src/main/ClasForm.scala
+++ b/modules/clas/src/main/ClasForm.scala
@@ -22,7 +22,7 @@ final class ClasForm(
         "teachers" -> nonEmptyText.verifying("Invalid teacher list", str => {
           val ids = readTeacherIds(str)
           ids.nonEmpty && ids.size <= 10 && ids.forall { id =>
-            blockingFetchUser(id.value).isDefined
+            blockingFetchUser(id).isDefined
           }
         })
       )(ClasData.apply)(ClasData.unapply)
@@ -64,7 +64,7 @@ final class ClasForm(
         mapping(
           "username" -> lila.user.DataForm.historicalUsernameField
             .verifying("Unknown username", { blockingFetchUser(_).isDefined })
-            .verifying("This is a teacher", u => !c.teachers.toList.exists(_.value == u.toLowerCase)),
+            .verifying("This is a teacher", u => !c.teachers.toList.exists(_ == u.toLowerCase)),
           "realName" -> nonEmptyText
         )(NewStudent.apply)(NewStudent.unapply)
       )
@@ -106,7 +106,7 @@ object ClasForm {
   }
 
   private def readTeacherIds(str: String) =
-    str.linesIterator.map(_.trim).filter(_.nonEmpty).map(User.normalize).distinct.map(Teacher.Id.apply).toList
+    str.linesIterator.map(_.trim).filter(_.nonEmpty).map(User.normalize).distinct.toList
 
   case class NewStudent(
       username: String,
diff --git a/modules/clas/src/main/Env.scala b/modules/clas/src/main/Env.scala
index 7d849b0f54..39043e99f1 100644
--- a/modules/clas/src/main/Env.scala
+++ b/modules/clas/src/main/Env.scala
@@ -45,7 +45,6 @@ final class Env(
 }
 
 private class ClasColls(db: lila.db.Db) {
-  val teacher = db(CollName("clas_teacher"))
   val clas    = db(CollName("clas_clas"))
   val student = db(CollName("clas_student"))
 }
diff --git a/modules/clas/src/main/Student.scala b/modules/clas/src/main/Student.scala
index 2b5ca2ddf3..cd5065b858 100644
--- a/modules/clas/src/main/Student.scala
+++ b/modules/clas/src/main/Student.scala
@@ -28,7 +28,7 @@ object Student {
 
   def id(userId: User.ID, clasId: Clas.Id) = Id(s"${userId}:${clasId}")
 
-  def make(user: User, clas: Clas, teacherId: Teacher.Id, realName: String, managed: Boolean) = Student(
+  def make(user: User, clas: Clas, teacherId: User.ID, realName: String, managed: Boolean) = Student(
     _id = id(user.id, clas.id),
     userId = user.id,
     clasId = clas.id,