diff --git a/backend/src/controllers/adminController.js b/backend/src/controllers/adminController.js
index ed6b3d6..6b330e2 100644
--- a/backend/src/controllers/adminController.js
+++ b/backend/src/controllers/adminController.js
@@ -243,9 +243,20 @@ function getUsers(req, res) {
 /* ── PATCH /api/admin/users/:id/role ─────────────────────────────────── */
 function updateRole(req, res) {
   const { role } = req.body;
-  const allowed = ['student', 'teacher', 'admin', 'free_student'];
-  if (!allowed.includes(role))
-    return res.status(400).json({ error: `role must be one of: ${allowed.join(', ')}` });
+  const BUILTIN = ['student', 'teacher', 'admin', 'free_student'];
+
+  // Кастомная роль: хранится как функциональная база (base_roles[0]) в users.role
+  // + имя в users.custom_role. Встроенная роль: role = built-in, custom_role = NULL.
+  let baseRole = role, customRole = null;
+  if (!BUILTIN.includes(role)) {
+    let cr = null;
+    try { cr = db.prepare('SELECT base_roles, is_builtin FROM roles WHERE name = ?').get(role); } catch (_e) { cr = null; }
+    if (!cr || cr.is_builtin) return res.status(400).json({ error: `Unknown role: ${role}` });
+    let bases = [];
+    try { bases = JSON.parse(cr.base_roles || '[]'); } catch (_e) { bases = []; }
+    baseRole = bases.find(b => BUILTIN.includes(b)) || 'student';
+    customRole = role;
+  }
 
   const user = db.prepare('SELECT id FROM users WHERE id = ?').get(req.params.id);
   if (!user) return res.status(404).json({ error: 'User not found' });
@@ -254,9 +265,10 @@ function updateRole(req, res) {
     return res.status(400).json({ error: 'Cannot change your own role' });
 
   const oldRole = db.prepare('SELECT role FROM users WHERE id = ?').get(req.params.id)?.role;
-  db.prepare('UPDATE users SET role = ?, token_version = token_version + 1 WHERE id = ?').run(role, req.params.id);
-  audit(req, 'user.role_change', `user:${req.params.id}`, `${oldRole} -> ${role}`);
-  res.json({ id: Number(req.params.id), role });
+  db.prepare('UPDATE users SET role = ?, custom_role = ?, token_version = token_version + 1 WHERE id = ?')
+    .run(baseRole, customRole, req.params.id);
+  audit(req, 'user.role_change', `user:${req.params.id}`, `${oldRole} -> ${customRole || baseRole}`);
+  res.json({ id: Number(req.params.id), role: customRole || baseRole, base: baseRole });
 }
 
 /* ── GET /api/admin/users/:id/sessions ───────────────────────────────── */
diff --git a/backend/src/db/migrations/055_user_custom_role.sql b/backend/src/db/migrations/055_user_custom_role.sql
new file mode 100644
index 0000000..21da666
--- /dev/null
+++ b/backend/src/db/migrations/055_user_custom_role.sql
@@ -0,0 +1,10 @@
+-- 055_user_custom_role.sql
+-- Phase C, Stage C-2 — присвоение кастомной роли пользователю.
+-- users.role в канон-схеме имеет CHECK (admin/teacher/student/free_student) и
+-- безопасно пересобрать users нельзя (FK многих таблиц, миграции в транзакции).
+-- Поэтому кастомную роль храним отдельной колонкой: users.role = функциональная
+-- БАЗА (встроенная роль для веток контроллеров и резолва прав), users.custom_role
+-- = имя кастомной роли (для гейтов через effectiveRoles + метка + C-3 пер-ролевые права).
+-- NULL = обычная встроенная роль.
+
+ALTER TABLE users ADD COLUMN custom_role TEXT;
diff --git a/backend/src/middleware/auth.js b/backend/src/middleware/auth.js
index 9037518..dbf5bae 100644
--- a/backend/src/middleware/auth.js
+++ b/backend/src/middleware/auth.js
@@ -16,7 +16,7 @@ function authMiddleware(req, res, next) {
   try {
     const payload = jwt.verify(token, process.env.JWT_SECRET, { algorithms: ['HS256'] });
     // Re-fetch role + token_version from DB so changes take effect immediately
-    const fresh = db.prepare('SELECT role, token_version, is_banned FROM users WHERE id = ?').get(payload.id);
+    const fresh = db.prepare('SELECT role, custom_role, token_version, is_banned FROM users WHERE id = ?').get(payload.id);
     if (!fresh) return res.status(401).json({ error: 'User not found' });
     if (fresh.is_banned) return res.status(403).json({ error: 'Аккаунт заблокирован' });
     // Invalidate tokens issued before password change / role change.
@@ -25,7 +25,7 @@ function authMiddleware(req, res, next) {
     if (fresh.token_version != null && payload.tv !== fresh.token_version) {
       return res.status(401).json({ error: 'Token revoked — please log in again' });
     }
-    req.user = { ...payload, role: fresh.role };
+    req.user = { ...payload, role: fresh.role, customRole: fresh.custom_role || null };
     next();
   } catch {
     res.status(401).json({ error: 'Token invalid or expired' });
@@ -52,7 +52,7 @@ function effectiveRoles(role) {
 
 function requireRole(...roles) {
   return (req, res, next) => {
-    const eff = effectiveRoles(req.user?.role);
+    const eff = effectiveRoles(req.user?.customRole || req.user?.role);
     if (eff.some(r => roles.includes(r))) return next();
     if (req.user) logDenied(req, 'forbidden', `роль ${req.user.role}; требуется ${roles.join('/')}`);
     return res.status(403).json({ error: 'Forbidden' });
@@ -137,10 +137,10 @@ function optionalAuth(req, res, next) {
   const token = header.slice(7);
   try {
     const payload = jwt.verify(token, process.env.JWT_SECRET, { algorithms: ['HS256'] });
-    const fresh = db.prepare('SELECT role, token_version, is_banned FROM users WHERE id = ?').get(payload.id);
+    const fresh = db.prepare('SELECT role, custom_role, token_version, is_banned FROM users WHERE id = ?').get(payload.id);
     if (fresh && !fresh.is_banned) {
       if (fresh.token_version == null || payload.tv === fresh.token_version) {
-        req.user = { ...payload, role: fresh.role };
+        req.user = { ...payload, role: fresh.role, customRole: fresh.custom_role || null };
       }
     }
   } catch {}
diff --git a/backend/tests/custom-roles.test.js b/backend/tests/custom-roles.test.js
index 92e6280..4751dca 100644
--- a/backend/tests/custom-roles.test.js
+++ b/backend/tests/custom-roles.test.js
@@ -8,7 +8,7 @@
  */
 const { describe, it, before, after } = require('node:test');
 const assert = require('node:assert/strict');
-const { db, cleanup } = require('./setup');
+const { db, getToken, inject, cleanup } = require('./setup');
 const auth = require('../src/middleware/auth');
 
 after(() => cleanup());
@@ -52,3 +52,35 @@ describe('custom roles — effectiveRoles (C-1)', () => {
     assert.equal(passes('student', ['teacher', 'admin']), false);
   });
 });
+
+describe('custom roles — назначение пользователю (C-2)', () => {
+  let adminToken;
+  before(async () => {
+    adminToken = (await getToken('admin')).token;
+    db.prepare("INSERT OR IGNORE INTO roles (name,label,base_roles,is_builtin) VALUES ('methodist','Методист',?,0)")
+      .run(JSON.stringify(['teacher']));
+  });
+
+  it('PATCH role=кастомная → users.role=база, custom_role=имя', async () => {
+    const u = await getToken('student');
+    const r = await inject('PATCH', `/api/admin/users/${u.userId}/role`, { role: 'methodist' }, adminToken);
+    assert.equal(r.status, 200, JSON.stringify(r.body));
+    assert.equal(r.body.base, 'teacher');
+    const row = db.prepare('SELECT role, custom_role FROM users WHERE id=?').get(u.userId);
+    assert.equal(row.role, 'teacher', 'функциональная база = teacher');
+    assert.equal(row.custom_role, 'methodist');
+
+    // обратно на встроенную → custom_role очищается
+    const r2 = await inject('PATCH', `/api/admin/users/${u.userId}/role`, { role: 'student' }, adminToken);
+    assert.equal(r2.status, 200);
+    const row2 = db.prepare('SELECT role, custom_role FROM users WHERE id=?').get(u.userId);
+    assert.equal(row2.role, 'student');
+    assert.equal(row2.custom_role, null);
+  });
+
+  it('PATCH с несуществующей ролью → 400', async () => {
+    const u = await getToken('student');
+    const bad = await inject('PATCH', `/api/admin/users/${u.userId}/role`, { role: 'ghostrole' }, adminToken);
+    assert.equal(bad.status, 400);
+  });
+});