diff --git a/hydro/handler/contest.js b/hydro/handler/contest.js
index fe2d5fa18..92e733723 100644
--- a/hydro/handler/contest.js
+++ b/hydro/handler/contest.js
@@ -12,8 +12,8 @@ const {
         PERM_VIEW_CONTEST, PERM_EDIT_CONTEST_SELF,
     },
     PRIV: {
-        PRIV_READ_RECORD_CODE
-    }
+        PRIV_READ_RECORD_CODE,
+    },
 } = require('../model/builtin');
 const contest = require('../model/contest');
 const document = require('../model/document');
diff --git a/hydro/handler/domain.js b/hydro/handler/domain.js
index 82d142d59..88096445b 100644
--- a/hydro/handler/domain.js
+++ b/hydro/handler/domain.js
@@ -2,9 +2,9 @@ const user = require('../model/user');
 const domain = require('../model/domain');
 const system = require('../model/system');
 const { DOMAIN_SETTINGS, DOMAIN_SETTINGS_BY_KEY } = require('../model/setting');
+const { PERM: { PERM_EDIT_DOMAIN }, PERMS_BY_FAMILY } = require('../model/builtin');
 const paginate = require('../lib/paginate');
 const { Route, Handler } = require('../service/server');
-const { PERM_MANAGE } = require('../model/builtin').PERM;
 const { RoleAlreadyExistError, ValidationError, PermissionError } = require('../error');
 
 class DomainRankHandler extends Handler {
@@ -55,7 +55,7 @@ class DomainCreateHandler extends Handler {
 
 class ManageHandler extends Handler {
     async prepare({ domainId }) {
-        this.checkPerm(PERM_MANAGE);
+        this.checkPerm(PERM_EDIT_DOMAIN);
         this.domain = await domain.get(domainId);
     }
 }
@@ -95,9 +95,8 @@ class DomainDashboardHandler extends ManageHandler {
 
 class DomainUserHandler extends ManageHandler {
     async get({ domainId }) {
-        const uids = [];
         const rudocs = {};
-        const [udocs, roles] = await Promise.all([
+        const [dudocs, roles] = await Promise.all([
             user.getMultiInDomain(domainId, {
                 $and: [
                     { role: { $ne: 'default' } },
@@ -106,17 +105,14 @@ class DomainUserHandler extends ManageHandler {
             }).toArray(),
             user.getRoles(domainId),
         ]);
+        const uids = dudocs.map((dudoc) => dudoc.uid);
+        const udict = await user.getList(domainId, uids);
         for (const role of roles) rudocs[role._id] = [];
-        for (const udoc of udocs) {
-            uids.push(udoc.uid);
-            const ud = user.getById(domainId, udoc.uid);
+        for (const dudoc of dudocs) {
+            const ud = udict[dudoc.uid];
             rudocs[ud.role].push(ud);
         }
-        const tasks = [];
-        for (const key in rudocs) tasks.push(Promise.all(rudocs[key]));
-        await Promise.all(tasks);
         const rolesSelect = roles.map((role) => [role._id, role._id]);
-        const udict = await user.getList(domainId, uids);
         const path = [
             ['Hydro', 'homepage'],
             ['domain', null],
@@ -143,7 +139,9 @@ class DomainPermissionHandler extends ManageHandler {
             ['domain_permission', null],
         ];
         this.response.template = 'domain_permission.html';
-        this.response.body = { roles, domain: this.domain, path };
+        this.response.body = {
+            roles, PERMS_BY_FAMILY, domain: this.domain, path,
+        };
     }
 
     async post({ domainId }) {
diff --git a/hydro/handler/misc.js b/hydro/handler/misc.js
index 593fce709..ac11584a5 100644
--- a/hydro/handler/misc.js
+++ b/hydro/handler/misc.js
@@ -49,8 +49,9 @@ class StatusUpdateHandler extends Handler {
 
 class SwitchLanguageHandler extends Handler {
     async get({ lang }) {
-        if (this.user.hasPriv(PRIV_USER_PROFILE)) await user.setById(this.user._id, { viewLang: lang });
-        else this.session.viewLang = lang;
+        if (this.user.hasPriv(PRIV_USER_PROFILE)) {
+            await user.setById(this.user._id, { viewLang: lang });
+        } else this.session.viewLang = lang;
         this.back();
     }
 }
diff --git a/hydro/handler/system.js b/hydro/handler/system.js
index 52cf5e7d4..26bdd5f96 100644
--- a/hydro/handler/system.js
+++ b/hydro/handler/system.js
@@ -2,13 +2,13 @@ const domain = require('../model/domain');
 const system = require('../model/system');
 const setting = require('../model/setting');
 const { Route, Handler } = require('../service/server');
-const { PERM_MANAGE } = require('../model/builtin').PERM;
+const { PRIV_EDIT_SYSTEM } = require('../model/builtin').PRIV;
 const hpm = require('../lib/hpm');
 const loader = require('../loader');
 
 class SystemHandler extends Handler {
     async prepare({ domainId }) {
-        this.checkPerm(PERM_MANAGE);
+        this.checkPriv(PRIV_EDIT_SYSTEM);
         this.domain = await domain.get(domainId);
     }
 }
diff --git a/hydro/handler/user.js b/hydro/handler/user.js
index 24971b5a2..28779dd9f 100644
--- a/hydro/handler/user.js
+++ b/hydro/handler/user.js
@@ -19,7 +19,7 @@ const {
         PERM_VIEW_PROBLEM_HIDDEN,
     },
     PRIV: {
-        PRIV_USER_PROFILE, PRIV_REGISTER_USER,
+        PRIV_USER_PROFILE, PRIV_REGISTER_USER, PRIV_NONE,
     },
 } = require('../model/builtin');
 
@@ -41,7 +41,7 @@ class UserLoginHandler extends Handler {
         if (!udoc) throw new LoginError(uname);
         if (udoc) udoc.checkPassword(password);
         await user.setById(udoc._id, { loginat: new Date(), loginip: this.request.ip });
-        if (udoc.ban) throw new BlacklistedError(uname);
+        if (udoc.priv === PRIV_NONE) throw new BlacklistedError(uname);
         this.session.uid = udoc._id;
         this.session.rememberme = rememberme;
         this.response.redirect = this.request.referer.endsWith('/login') ? '/' : this.request.referer;
diff --git a/hydro/lib/nav.js b/hydro/lib/nav.js
index e109130d4..339f24512 100644
--- a/hydro/lib/nav.js
+++ b/hydro/lib/nav.js
@@ -1,14 +1,19 @@
 const { isNull } = require('lodash');
-
-const permission = require('../model/builtin').PERM;
+const { PRIV, PERM } = require('../model/builtin');
 
 global.Hydro.ui.nav = [];
 
 const trueChecker = () => true;
+const Checker = (perm, priv, checker = trueChecker) => (handler) => (
+    checker(handler)
+    && (perm ? handler.user.hasPerm(perm) : true)
+    && (priv ? handler.user.hasPriv(priv) : true)
+);
+
 const Item = (name, args, prefix, ...permPrivChecker) => {
     let _priv;
     let _perm;
-    let checker;
+    let checker = trueChecker;
     for (const item of permPrivChecker) {
         if (typeof item === 'object' && !isNull(item)) {
             if (typeof item.call !== 'undefined') {
@@ -24,27 +29,21 @@ const Item = (name, args, prefix, ...permPrivChecker) => {
             _perm = item;
         }
     }
-    if ((_perm || _priv) && checker) {
-        checker = ((_chk) => (handler) => _chk(handler)
-            && (_perm ? handler.user.hasPerm(_perm) : true)
-            && (_priv ? handler.user.hasPriv(_priv) : true))(checker);
-    } else if (_perm) {
-        checker = (handler) => handler.user.hasPerm(_perm);
-    } else if (!checker) checker = trueChecker;
+    checker = Checker(_perm, _priv, checker);
     global.Hydro.ui.nav.push({
         name, args: args || {}, prefix, checker,
     });
 };
 
 Item('homepage', null, 'homepage');
-Item('problem_main', null, 'problem', permission.PERM_VIEW_PROBLEM);
-Item('training_main', null, 'training', permission.PERM_VIEW_TRAINING);
-Item('homework_main', null, 'homework', permission.PERM_VIEW_HOMEWORK);
-Item('discussion_main', null, 'discussion', permission.PERM_VIEW_DISCUSSION);
-Item('contest_main', null, 'contest', permission.PERM_VIEW_CONTEST);
+Item('problem_main', null, 'problem', PERM.PERM_VIEW_PROBLEM);
+Item('training_main', null, 'training', PERM.PERM_VIEW_TRAINING);
+Item('homework_main', null, 'homework', PERM.PERM_VIEW_HOMEWORK);
+Item('discussion_main', null, 'discussion', PERM.PERM_VIEW_DISCUSSION);
+Item('contest_main', null, 'contest', PERM.PERM_VIEW_CONTEST);
 Item('record_main', null, 'record');
 Item('ranking', null, 'ranking');
-Item('domain_dashboard', null, 'domain', permission.PERM_MANAGE);
-Item('manage_dashboard', null, 'manage', null, (handler) => handler.user.priv === 1);
+Item('domain_dashboard', null, 'domain', PERM.PERM_EDIT_DOMAIN);
+Item('manage_dashboard', null, 'manage', PRIV.PRIV_SET_PRIV);
 
 global.Hydro.lib.nav = module.exports = Item;
diff --git a/hydro/model/builtin.js b/hydro/model/builtin.js
index 1bf700455..8a4c2dca0 100644
--- a/hydro/model/builtin.js
+++ b/hydro/model/builtin.js
@@ -73,6 +73,9 @@ const PERM = {
     PERM_CREATE_TRAINING: 't',
     PERM_EDIT_TRAINING: 'u',
     PERM_EDIT_TRAINING_SELF: 'v',
+
+    // Ranking
+    PERM_VIEW_RANKING: 'w',
 };
 
 const Permission = (family, key, desc) => ({ family, key, desc });
@@ -206,7 +209,7 @@ PERM.PERM_ADMIN = PERM.PERM_ALL;
 
 const PRIV = {
     PRIV_NONE: 0,
-    PRIV_SET_PRIV: 1 << 0,
+    PRIV_EDIT_SYSTEM: 1 << 0, // renamed from PRIV_SET_PRIV
     PRIV_SET_PERM: 1 << 1,
     PRIV_USER_PROFILE: 1 << 2,
     PRIV_REGISTER_USER: 1 << 3,
diff --git a/hydro/model/domain.js b/hydro/model/domain.js
index f1fef8305..45702737a 100644
--- a/hydro/model/domain.js
+++ b/hydro/model/domain.js
@@ -15,12 +15,23 @@ const coll = db.collection('domain');
  * @param {string} domainId
  * @param {number} owner
  */
-function add(domainId, owner, name) {
-    const tasks = [
-        coll.insertOne({
-            _id: domainId, owner, name, bulletin: '',
-        }),
-    ];
+function add(domainId, owner, name, isEnsure = false) {
+    const tasks = [];
+    if (isEnsure) {
+        tasks.push(
+            coll.updateOne(
+                { _id: domainId },
+                { $set: { owner }, $setOnInsert: { name, bulletin: '' } },
+                { upsert: true },
+            ),
+        );
+    } else {
+        tasks.push(
+            coll.insertOne({
+                _id: domainId, owner, name, bulletin: '',
+            }),
+        );
+    }
     for (const id in builtin.BUILTIN_ROLES) {
         tasks.push(
             document.add(
diff --git a/hydro/model/problem.js b/hydro/model/problem.js
index 30bd5417a..6a5e2191f 100644
--- a/hydro/model/problem.js
+++ b/hydro/model/problem.js
@@ -1,10 +1,10 @@
+const { ObjectId } = require('bson');
 const { STATUS_ACCEPTED } = require('./builtin').STATUS;
 const file = require('./file');
 const document = require('./document');
 const domain = require('./domain');
 const { ProblemNotFoundError } = require('../error');
 const readConfig = require('../lib/readConfig');
-const { ObjectId } = require('bson');
 
 /**
  * @typedef {import('../interface').Pdoc} Pdoc
diff --git a/hydro/model/setting.js b/hydro/model/setting.js
index 5cafd0a63..63d71eca0 100644
--- a/hydro/model/setting.js
+++ b/hydro/model/setting.js
@@ -12,18 +12,20 @@ const timezones = Array.from(tzs).sort().map((tz) => [tz, tz]);
 const PREFERENCE_SETTINGS = [];
 const ACCOUNT_SETTINGS = [];
 const DOMAIN_SETTINGS = [];
+const DOMAIN_USER_SETTINGS = [];
 const SYSTEM_SETTINGS = [];
 const SETTINGS = [];
 const SETTINGS_BY_KEY = {};
+const DOMAIN_USER_SETTINGS_BY_KEY = {};
 const DOMAIN_SETTINGS_BY_KEY = {};
 const SYSTEM_SETTINGS_BY_KEY = {};
 
 const Setting = (
     family, key, range = null,
     value = null, ui = 'text', name = '',
-    desc = '',
+    desc = '', hidden = false,
 ) => ({
-    family, key, range, value, ui, name, desc,
+    family, key, range, value, ui, name, desc, hidden,
 });
 
 const PreferenceSetting = (...settings) => {
@@ -40,6 +42,12 @@ const AccountSetting = (...settings) => {
         SETTINGS_BY_KEY[setting.key] = setting;
     }
 };
+const DomainUserSetting = (...settings) => {
+    for (const setting of settings) {
+        DOMAIN_USER_SETTINGS.push(setting);
+        DOMAIN_USER_SETTINGS_BY_KEY[setting.key] = setting;
+    }
+};
 const DomainSetting = (...settings) => {
     for (const setting of settings) {
         DOMAIN_SETTINGS.push(setting);
@@ -119,6 +127,7 @@ global.Hydro.model.setting = module.exports = {
     PreferenceSetting,
     AccountSetting,
     DomainSetting,
+    DomainUserSetting,
     SystemSetting,
     PREFERENCE_SETTINGS,
     ACCOUNT_SETTINGS,
@@ -128,4 +137,6 @@ global.Hydro.model.setting = module.exports = {
     SYSTEM_SETTINGS_BY_KEY,
     DOMAIN_SETTINGS,
     DOMAIN_SETTINGS_BY_KEY,
+    DOMAIN_USER_SETTINGS,
+    DOMAIN_USER_SETTINGS_BY_KEY,
 };
diff --git a/hydro/model/user.js b/hydro/model/user.js
index f19bd1fdc..d80c5fdaa 100644
--- a/hydro/model/user.js
+++ b/hydro/model/user.js
@@ -1,4 +1,4 @@
-const builtin = require('./builtin');
+const { BUILTIN_ROLES, BUILTIN_USERS, PRIV } = require('./builtin');
 const document = require('./document');
 const system = require('./system');
 const token = require('./token');
@@ -6,7 +6,6 @@ const setting = require('./setting');
 const { UserNotFoundError, UserAlreadyExistError, LoginError } = require('../error');
 const pwhash = require('../lib/hash.hydro');
 const db = require('../service/db');
-const { PRIV } = require('./builtin');
 
 const coll = db.collection('user');
 
@@ -63,13 +62,13 @@ async function getInDomain(domainId, udoc) {
     // eslint-disable-next-line no-bitwise
     if (udoc.priv & PRIV.PRIV_MANAGE_ALL_DOMAIN) dudoc.role = 'admin';
     const p = await document.get(domainId, document.TYPE_DOMAIN_USER, dudoc.role || 'default');
-    dudoc.perm = p ? p.content : builtin.BUILTIN_ROLES[dudoc.role || 'default'].perm;
+    dudoc.perm = p ? p.content : BUILTIN_ROLES[dudoc.role || 'default'].perm;
     return dudoc;
 }
 
 async function getById(domainId, _id, throwError = false) {
     const udoc = _id === 0 || _id === 1
-        ? builtin.BUILTIN_USERS[_id]
+        ? BUILTIN_USERS[_id]
         : await coll.findOne({ _id });
     if (!udoc) {
         if (throwError) throw new UserNotFoundError(_id);
@@ -90,9 +89,9 @@ async function getList(domainId, uids) {
 async function getByUname(domainId, uname, ignoreMissing = false) {
     const unameLower = uname.trim().toLowerCase();
     const udoc = (unameLower === 'guest')
-        ? builtin.BUILTIN_USERS[0]
+        ? BUILTIN_USERS[0]
         : unameLower === 'hydro'
-            ? builtin.BUILTIN_USERS[1]
+            ? BUILTIN_USERS[1]
             : await coll.findOne({ unameLower });
     if (!udoc) {
         if (ignoreMissing) return null;
@@ -105,9 +104,9 @@ async function getByUname(domainId, uname, ignoreMissing = false) {
 async function getByEmail(domainId, mail, ignoreMissing = false) {
     const mailLower = mail.trim().toLowerCase();
     const udoc = (mailLower === 'guest@hydro.local')
-        ? builtin.BUILTIN_USERS[0]
+        ? BUILTIN_USERS[0]
         : mailLower === 'hydro@hydro.local'
-            ? builtin.BUILTIN_USERS[1]
+            ? BUILTIN_USERS[1]
             : await coll.findOne({ mailLower });
     if (!udoc) {
         if (ignoreMissing) return null;
@@ -259,15 +258,11 @@ function deleteRoles(domainId, roles) {
 
 function ban(uid) {
     return Promise.all([
-        coll.updateOne({ _id: uid }, { $set: { ban: true } }),
+        setPriv(uid, PRIV.PRIV_NONE),
         token.delByUid(uid),
     ]);
 }
 
-function setSuperAdmin(uid) {
-    return setById(uid, { priv: 1 });
-}
-
 function ensureIndexes() {
     return Promise.all([
         coll.createIndex('unameLower', { unique: true }),
@@ -300,7 +295,6 @@ global.Hydro.model.user = module.exports = {
     getInDomain,
     addRole,
     deleteRoles,
-    setSuperAdmin,
     ban,
     ensureIndexes,
 };
diff --git a/hydro/script/deleteUser.js b/hydro/script/deleteUser.js
index 0007683ad..8e3c8d8bd 100644
--- a/hydro/script/deleteUser.js
+++ b/hydro/script/deleteUser.js
@@ -4,7 +4,7 @@ const document = require('../model/document');
 const setting = require('../model/setting');
 const db = require('../service/db');
 const paginate = require('../lib/paginate');
-const { STATUS } = require('../model/builtin');
+const { STATUS, PRIV } = require('../model/builtin');
 
 const collDocument = db.collection('document');
 const collStatus = db.collection('document.status');
@@ -78,7 +78,7 @@ async function run({
     await user.setById(uid, {
         uname,
         unameLower: uname.toLowerCase(),
-        priv: 0,
+        priv: PRIV.PRIV_NONE,
     }, $unset);
     await user.setPassword(uid, String.random(32));
     // TODO delete contest, homework, etc
diff --git a/hydro/script/install.js b/hydro/script/install.js
index 995d59d68..f9e8dfeac 100644
--- a/hydro/script/install.js
+++ b/hydro/script/install.js
@@ -1,5 +1,6 @@
 const { defaults } = require('lodash');
 const db = require('../service/db');
+const { PRIV_ALL } = require('../model/builtin').PRIV;
 const system = require('../model/system');
 const domain = require('../model/domain');
 const pwhash = require('../lib/hash.hydro');
@@ -43,27 +44,7 @@ async function run({ username, password } = {}) {
         }));
     }
     await Promise.all(tasks);
-    tasks = [
-        domain.add('system', 0, 'Hydro').catch(() => domain.edit('system', { owner: 0, name: 'Hydro' })),
-        collUser.updateOne({ _id: 0 }, {
-            $set: defaults({
-                _id: 0,
-                uname: 'Hydro',
-                unameLower: 'hydro',
-                mail: 'hydro@hydro',
-                mailLower: 'hydro@hydro',
-            }, udoc),
-        }, { upsert: true }),
-        collUser.updateOne({ _id: 1 }, {
-            $set: defaults({
-                _id: 1,
-                mail: 'guest@hydro',
-                mailLower: 'guest@hydro',
-                uname: 'Guest',
-                unameLower: 'guest',
-            }, udoc),
-        }, { upsert: true }),
-    ];
+    tasks = [domain.add('system', 0, 'Hydro', true)];
     if (username && password) {
         const salt = String.random();
         tasks.push(
@@ -77,7 +58,7 @@ async function run({ username, password } = {}) {
                     hash: pwhash(password, salt),
                     salt,
                     gravatar: 'root@hydro',
-                    priv: 1,
+                    priv: PRIV_ALL,
                 }, udoc),
             }, { upsert: true }),
         );
diff --git a/hydro/script/setSuperadmin.js b/hydro/script/setSuperadmin.js
index 39602e17e..fc591efd1 100644
--- a/hydro/script/setSuperadmin.js
+++ b/hydro/script/setSuperadmin.js
@@ -1,11 +1,12 @@
 const user = require('../model/user');
+const { PRIV_ALL } = require('../model/builtin').PRIV;
 
 async function run({
     uid,
 }) {
     uid = parseInt(uid, 10);
     if (Number.isNaN(uid)) throw new Error('uid');
-    await user.setSuperAdmin(uid);
+    await user.setPriv(uid, PRIV_ALL);
     return uid;
 }
 
diff --git a/templates/domain_permission.html b/templates/domain_permission.html
index fbdc6b8c4..7816da8a6 100644
--- a/templates/domain_permission.html
+++ b/templates/domain_permission.html
@@ -21,7 +21,7 @@
         {% endfor %}
         </tr>
       </thead>
-    {% for family, perms in perm.PERMS_BY_FAMILY %}
+    {% for family, perms in PERMS_BY_FAMILY %}
       <tbody>
         <tr>
           <td class="col--family" colspan="{{ (roles|length)+1 }}">
diff --git a/templates/partials/setting.html b/templates/partials/setting.html
index c89a14fab..9b74b57fd 100644
--- a/templates/partials/setting.html
+++ b/templates/partials/setting.html
@@ -5,6 +5,7 @@
   </div>
   <div class="section__body">
   {% for setting in family_settings %}
+  {% if not setting.hidden %}
   {% if setting.ui == 'text' or setting.ui == 'password' or setting.ui == 'number' %}
     {{ form.form_text({
           type:setting.ui,
@@ -61,6 +62,7 @@
           value:current[setting.key] or setting.value
     })}}
   {% endif %}
+  {% endif %}
   {% endfor %}
   </div>
 {% endfor %}