diff --git a/install/multi.php b/install/multi.php
new file mode 100644
index 00000000..c3a6bada
--- /dev/null
+++ b/install/multi.php
@@ -0,0 +1,276 @@
+<?php
+
+#################################################################################
+##              -= YOU MAY NOT REMOVE OR CHANGE THIS NOTICE =-                 ##
+## --------------------------------------------------------------------------- ##
+##  Project:       TravianZ                                                    ##
+##  Filename       multi.php                                                   ##
+##  Type           : Multi-instance installation manager                       ##
+##  Project        : TravianZ                                                  ##
+##  Source code    : https://github.com/Shadowss/TravianZ                      ##
+#################################################################################
+
+// Multi-instance installer manager.
+//
+// The normal TravianZ installer remains available for the legacy/default world.
+// This page manages isolated worlds from one code installation. Each world gets
+// its own config.php, database target, runtime directory and installed marker.
+
+@set_time_limit(0);
+@session_start();
+
+$root = dirname(__DIR__);
+$instancesDir = $root . DIRECTORY_SEPARATOR . 'instances';
+$registryFile = $instancesDir . DIRECTORY_SEPARATOR . 'registry.json';
+
+if (!is_dir($instancesDir)) {
+    @mkdir($instancesDir, 0775, true);
+}
+
+function tz_multi_registry_read($file) {
+    if (!is_file($file)) {
+        return [];
+    }
+
+    $data = json_decode((string) @file_get_contents($file), true);
+    return is_array($data) ? $data : [];
+}
+
+function tz_multi_registry_write($file, array $data) {
+    $tmp = $file . '.tmp';
+    $json = json_encode($data, JSON_PRETTY_PRINT | JSON_UNESCAPED_SLASHES);
+
+    if ($json === false || @file_put_contents($tmp, $json . PHP_EOL, LOCK_EX) === false) {
+        return false;
+    }
+
+    if (!@rename($tmp, $file)) {
+        @unlink($tmp);
+        return false;
+    }
+
+    return true;
+}
+
+$registry = tz_multi_registry_read($registryFile);
+$message = '';
+$error = '';
+
+if ($_SERVER['REQUEST_METHOD'] === 'POST' && isset($_POST['create_definitions'])) {
+    $count = isset($_POST['server_count']) ? (int) $_POST['server_count'] : 1;
+    $count = max(1, min(100, $count));
+
+    $newRegistry = $registry;
+    $usedIds = [];
+
+    for ($i = 1; $i <= $count; $i++) {
+        $id = strtolower(trim((string) ($_POST['instance_id'][$i] ?? '')));
+        $name = trim((string) ($_POST['instance_name'][$i] ?? ''));
+        $host = trim((string) ($_POST['instance_host'][$i] ?? ''));
+        $db = trim((string) ($_POST['instance_db'][$i] ?? ''));
+        $prefix = trim((string) ($_POST['instance_prefix'][$i] ?? ''));
+
+        if ($id === '') {
+            $id = 's' . $i;
+        }
+
+        if (!preg_match('/^[a-z0-9][a-z0-9_-]{0,31}$/', $id)) {
+            $error = 'Instance ID invalid la serverul ' . $i . '. Foloseste doar litere mici, cifre, _ sau -.';
+            break;
+        }
+
+        if (isset($usedIds[$id])) {
+            $error = 'Instance ID duplicat: ' . htmlspecialchars($id, ENT_QUOTES, 'UTF-8');
+            break;
+        }
+        $usedIds[$id] = true;
+
+        if ($name === '') {
+            $name = 'TravianZ ' . strtoupper($id);
+        }
+
+        if ($db === '') {
+            $db = 'travian_' . preg_replace('/[^a-zA-Z0-9_]/', '_', $id);
+        }
+
+        if ($prefix === '') {
+            $prefix = $id . '_';
+        }
+
+        if (!preg_match('/^[A-Za-z0-9_$]+_$/', $prefix)) {
+            $error = 'Prefix invalid la serverul ' . $i . '.';
+            break;
+        }
+
+        $instancePath = $instancesDir . DIRECTORY_SEPARATOR . $id;
+        if (!is_dir($instancePath) && !@mkdir($instancePath, 0775, true)) {
+            $error = 'Nu pot crea directorul instanței ' . $id . '.';
+            break;
+        }
+
+        $runtimePath = $instancePath . DIRECTORY_SEPARATOR . 'runtime';
+        if (!is_dir($runtimePath)) {
+            @mkdir($runtimePath, 0775, true);
+        }
+
+        $newRegistry[$id] = [
+            'id' => $id,
+            'name' => $name,
+            'host' => $host,
+            'database' => $db,
+            'prefix' => $prefix,
+            'status' => $newRegistry[$id]['status'] ?? 'defined',
+            'created_at' => $newRegistry[$id]['created_at'] ?? date('c'),
+        ];
+    }
+
+    if ($error === '') {
+        if (!tz_multi_registry_write($registryFile, $newRegistry)) {
+            $error = 'Nu pot scrie registry.json. Verifica permisiunile directorului instances/.';
+        } else {
+            $registry = $newRegistry;
+            $message = 'Instanțele au fost definite. Acum configurează fiecare server și pornește pașii de instalare.';
+        }
+    }
+}
+
+$selected = strtolower(trim((string) ($_GET['instance'] ?? '')));
+if ($selected !== '' && !isset($registry[$selected])) {
+    $selected = '';
+}
+
+$serverCount = isset($_POST['server_count']) ? max(1, min(100, (int) $_POST['server_count'])) : max(1, count($registry));
+if ($serverCount < 1) {
+    $serverCount = 1;
+}
+?>
+<!DOCTYPE html>
+<html lang="en">
+<head>
+    <meta charset="utf-8">
+    <title>TravianZ Multi-Instance Installer</title>
+    <style>
+        body{font-family:Arial,sans-serif;background:#eee;margin:0;padding:30px;color:#333}
+        .wrap{max-width:1200px;margin:auto;background:#fff;padding:25px;border-radius:8px}
+        h1{margin-top:0}.notice{padding:12px;margin:15px 0;background:#e8f5e9}.error{padding:12px;margin:15px 0;background:#ffebee}
+        .toolbar{display:flex;gap:12px;align-items:center;margin:20px 0}.toolbar input{width:80px;padding:8px}
+        .server{border:1px solid #ccc;padding:18px;margin:12px 0;border-radius:6px;background:#fafafa}
+        .grid{display:grid;grid-template-columns:repeat(5,1fr);gap:12px}.field label{display:block;font-weight:bold;margin-bottom:5px}.field input{width:100%;box-sizing:border-box;padding:9px}
+        button,.btn{padding:9px 15px;cursor:pointer;text-decoration:none;border:1px solid #aaa;background:#f6f6f6;color:#222;border-radius:4px;display:inline-block}
+        .btn-primary{background:#2d6cdf;color:#fff;border-color:#2d6cdf}.btn-success{background:#2e7d32;color:#fff;border-color:#2e7d32}.btn-warning{background:#ef6c00;color:#fff;border-color:#ef6c00}
+        .muted{color:#666;font-size:13px}.status{font-weight:bold}.actions{display:flex;flex-wrap:wrap;gap:8px;margin-top:15px}
+        code{background:#f1f1f1;padding:2px 5px}.step{padding:4px 8px;border-radius:4px;background:#eee;margin-right:5px;font-size:12px}
+        @media(max-width:900px){.grid{grid-template-columns:1fr 1fr}.wrap{padding:15px}}
+    </style>
+    <script>
+        function buildServers() {
+            const count = Math.max(1, Math.min(100, parseInt(document.getElementById('server_count').value || '1', 10)));
+            document.getElementById('server_count_post').value = count;
+            const box = document.getElementById('servers');
+            const existing = {};
+            Array.from(box.querySelectorAll('.server')).forEach(function(el){
+                const id = el.querySelector('[data-field="id"]');
+                if (id) existing[el.dataset.index] = {
+                    id: id.value,
+                    name: el.querySelector('[data-field="name"]').value,
+                    host: el.querySelector('[data-field="host"]').value,
+                    db: el.querySelector('[data-field="db"]').value,
+                    prefix: el.querySelector('[data-field="prefix"]').value
+                };
+            });
+            box.innerHTML = '';
+            for (let i = 1; i <= count; i++) {
+                const old = existing[i] || {};
+                const id = old.id || ('s' + i);
+                const div = document.createElement('div');
+                div.className = 'server';
+                div.dataset.index = i;
+                div.innerHTML = '<h3>Server ' + i + '</h3>' +
+                    '<div class="grid">' +
+                    '<div class="field"><label>Instance ID</label><input data-field="id" name="instance_id['+i+']" value="'+escapeHtml(id)+'" required></div>' +
+                    '<div class="field"><label>Server name</label><input data-field="name" name="instance_name['+i+']" value="'+escapeHtml(old.name || ('TravianZ '+id.toUpperCase()))+'" required></div>' +
+                    '<div class="field"><label>Hostname / domain</label><input data-field="host" name="instance_host['+i+']" value="'+escapeHtml(old.host || '')+'"></div>' +
+                    '<div class="field"><label>Database name</label><input data-field="db" name="instance_db['+i+']" value="'+escapeHtml(old.db || ('travian_'+id))+'" required></div>' +
+                    '<div class="field"><label>Table prefix</label><input data-field="prefix" name="instance_prefix['+i+']" value="'+escapeHtml(old.prefix || (id+'_'))+'" required></div>' +
+                    '</div>';
+                box.appendChild(div);
+            }
+        }
+        function escapeHtml(value) {
+            return String(value).replace(/&/g,'&amp;').replace(/</g,'&lt;').replace(/>/g,'&gt;').replace(/"/g,'&quot;');
+        }
+        window.addEventListener('DOMContentLoaded', function(){
+            const count = document.getElementById('server_count');
+            if (count && !document.querySelector('#servers .server')) buildServers();
+        });
+    </script>
+</head>
+<body>
+<div class="wrap">
+    <h1>TravianZ Multi-Instance Installer</h1>
+    <p class="muted">O singură instalare TravianZ, mai multe lumi izolate. Fiecare instanță are propriul config.php, database, runtime și marker <code>installed</code>.</p>
+
+    <?php if ($message !== ''): ?><div class="notice"><?=htmlspecialchars($message, ENT_QUOTES, 'UTF-8')?></div><?php endif; ?>
+    <?php if ($error !== ''): ?><div class="error"><?=htmlspecialchars($error, ENT_QUOTES, 'UTF-8')?></div><?php endif; ?>
+
+    <h2>1. Definește serverele</h2>
+    <div class="toolbar">
+        <label for="server_count"><strong>Număr servere:</strong></label>
+        <input id="server_count" name="server_count_ui" type="number" min="1" max="100" value="<?=$serverCount?>" onchange="buildServers()" oninput="buildServers()">
+    </div>
+
+    <form method="post">
+        <input type="hidden" name="server_count" id="server_count_post" value="<?=$serverCount?>">
+        <input type="hidden" name="create_definitions" value="1">
+        <div id="servers">
+<?php $i = 0; foreach ($registry as $instance): $i++; ?>
+            <div class="server" data-index="<?=$i?>">
+                <h3>Server <?=$i?></h3>
+                <div class="grid">
+                    <div class="field"><label>Instance ID</label><input data-field="id" name="instance_id[<?=$i?>]" value="<?=htmlspecialchars($instance['id'], ENT_QUOTES, 'UTF-8')?>" required></div>
+                    <div class="field"><label>Server name</label><input data-field="name" name="instance_name[<?=$i?>]" value="<?=htmlspecialchars($instance['name'], ENT_QUOTES, 'UTF-8')?>" required></div>
+                    <div class="field"><label>Hostname / domain</label><input data-field="host" name="instance_host[<?=$i?>]" value="<?=htmlspecialchars($instance['host'] ?? '', ENT_QUOTES, 'UTF-8')?>"></div>
+                    <div class="field"><label>Database name</label><input data-field="db" name="instance_db[<?=$i?>]" value="<?=htmlspecialchars($instance['database'], ENT_QUOTES, 'UTF-8')?>" required></div>
+                    <div class="field"><label>Table prefix</label><input data-field="prefix" name="instance_prefix[<?=$i?>]" value="<?=htmlspecialchars($instance['prefix'], ENT_QUOTES, 'UTF-8')?>" required></div>
+                </div>
+            </div>
+<?php endforeach; ?>
+        </div>
+        <button class="btn-primary" type="submit">Save server definitions</button>
+    </form>
+
+    <h2 style="margin-top:35px">2. Install each world</h2>
+<?php if (!$registry): ?>
+    <p class="muted">Nu există încă instanțe. Definește cel puțin un server mai sus.</p>
+<?php else: ?>
+<?php foreach ($registry as $id => $instance): ?>
+    <div class="server">
+        <h3><?=htmlspecialchars($instance['name'], ENT_QUOTES, 'UTF-8')?> <small>(<?=htmlspecialchars($id, ENT_QUOTES, 'UTF-8')?>)</small></h3>
+        <p>
+            <span class="step">DB: <?=htmlspecialchars($instance['database'], ENT_QUOTES, 'UTF-8')?></span>
+            <span class="step">Prefix: <?=htmlspecialchars($instance['prefix'], ENT_QUOTES, 'UTF-8')?></span>
+            <span class="status">Status: <?=htmlspecialchars($instance['status'] ?? 'defined', ENT_QUOTES, 'UTF-8')?></span>
+        </p>
+        <div class="actions">
+            <a class="btn btn-primary" href="config_instance.php?instance=<?=rawurlencode($id)?>">Configure server</a>
+<?php if (($instance['status'] ?? '') === 'configured'): ?>
+            <form method="post" action="process_instance.php" style="display:inline"><input type="hidden" name="instance_id" value="<?=htmlspecialchars($id, ENT_QUOTES, 'UTF-8')?>"><input type="hidden" name="action" value="structure"><button class="btn-warning" type="submit">Create database structure</button></form>
+<?php endif; ?>
+<?php if (($instance['status'] ?? '') === 'structure_created'): ?>
+            <form method="post" action="process_instance.php" style="display:inline"><input type="hidden" name="instance_id" value="<?=htmlspecialchars($id, ENT_QUOTES, 'UTF-8')?>"><input type="hidden" name="action" value="world"><button class="btn-warning" type="submit">Create world data</button></form>
+<?php endif; ?>
+<?php if (($instance['status'] ?? '') === 'world_created'): ?>
+            <form method="post" action="process_instance.php" style="display:inline"><input type="hidden" name="instance_id" value="<?=htmlspecialchars($id, ENT_QUOTES, 'UTF-8')?>"><input type="hidden" name="action" value="finalize"><button class="btn-success" type="submit">Finish installation</button></form>
+<?php endif; ?>
+<?php if (($instance['status'] ?? '') === 'installed'): ?>
+            <span class="btn btn-success">Installed</span>
+<?php endif; ?>
+        </div>
+    </div>
+<?php endforeach; ?>
+<?php endif; ?>
+
+    <p style="margin-top:30px"><a href="index.php">← Back to normal installer</a></p>
+</div>
+</body>
+</html>