English

Impostor is a horror-survival mod for Minecraft Fabric 1.20.1 that brings a new kind of psychological threat to multiplayer servers. Instead of spawning new monsters, it secretly possesses real online players, turning them into puppet-like entities controlled by a hidden AI — all while they look and move exactly like a normal human being.

Unlike traditional mob-spawning horror mods, Impostor works within the boundaries of player behavior. The possessed player eats, follows, fights mobs, chats, and even crouches — making it nearly impossible for others to tell who is real and who is not. The horror is not in what you see, but in what you trust.

Two Types of Impostors

Evil Impostor (Bad)

The Evil Impostor is a predatory entity. Once it takes hold of a player, it quietly observes, builds false trust, and then strikes.

Behavioral Phases:

Phase Duration Description Mimicking ~5s Immediately follows the target. Attacks nearby hostile mobs to appear helpful. Judging 5–8 min (configurable) Follows the target at a safe distance. Randomly switches between following, slow approaching, strafing, crouching, and looking around — mimicking natural player behavior. Disguise 1 ~15s Slowly closes in on the target. Renames itself to a fake player name. Killing 30s max Full-speed chase. Attacks the target every 0.75 seconds with configurable damage. If the target is not killed within 30 seconds, retreats to Disguise 2. Disguise 2 ~15s Repeats the closing-in routine under a new disguise. Enables wall-climbing. Killing (loop) Repeats Attacks again. This loop continues indefinitely. Chain Possession Mechanic: When the Evil Impostor successfully kills its target, it does not simply disappear. Instead:

The killed player is silently revived at the same location with full health. That newly revived player is immediately repossessed as a new Evil Impostor. The original impostor is then freed. This means a single Impostor can silently transfer from player to player across the server.

Combat Reactions: When attacked, the Evil Impostor reacts dynamically:

Crouch-cycle (35% chance) — crouches and stands repeatedly, mimicking a panicking player Dodge (35%) — strafes or moves away Fight back (10%) — counters immediately Flee (10%) — runs away briefly Freeze (5%) — stops completely, as if stunned Vanish (5%) — instantly releases, disappearing without a trace

Kind Impostor (Good)

The Kind Impostor is a passive, wandering entity. It never attacks players.

Behavior:

Follows the closest player and stays nearby (configurable follow distance). When no player is nearby, wanders freely: random walks, idle standing, looking around, crouching and standing, strafing, and even occasionally "mining" or "placing" blocks. Actively attacks nearby hostile mobs, acting as a bodyguard. Never enters a killing state. Cannot be force-attacked via command. The Kind Impostor creates an uncanny, companion-like presence — something that feels almost friendly, yet fundamentally wrong.

Trigger Conditions (Automatic) The mod monitors players passively. Possession is triggered automatically when:

A player has been isolated (away from all other players) for a configurable time window (default: 60s–180s). The current time is nighttime (configurable, default: night only). A random roll passes the trigger chance (default: 20%). No possession cooldown is active for that player (default: 30-minute cooldown after being released). The player does not have respawn immunity (default: 60s after respawn). The maximum number of simultaneous possessions has not been reached (default: 1). When triggered, the system picks a target player within range and begins possession. The type (Good/Bad) is determined by a configurable probability.

Pathfinding AI All possessed player movement uses a custom AI pathfinding engine written from scratch, because Minecraft's internal pathfinding system only supports MobEntity and is incompatible with ServerPlayerEntity.

The pathfinder:

Checks 8 horizontal directions + up/down jumps per node Validates each position for player-sized collision (2-block tall body) Caches computed paths for 15 ticks to reduce server load Falls back to straight-line movement if no path is found Maximum 1,500 iterations per calculation to prevent server lag Voice System The mod includes an optional voice mimicry system that records short audio clips from players and plays them back in distorted, eerie ways:

Pitch shifting (randomized range) Reversed playback (5% chance) Trimmed or repeated clips Playback intervals: 15–45 seconds (configurable) Chat System The possessed player occasionally sends chat messages to blend in:

Sends confused or surprised messages when attacked (30% chance) Sends random ambient chat at very low frequency (0.5% per tick) Messages are available in both Chinese and English based on per-player language settings Visual Effects (Client) When a player is possessed, a client-side packet is sent to update visual state:

A custom skin overlay can be applied (configurable null-skin texture) The player's nametag is replaced with a fake player name during killing phases After release, all visual effects are reverted Command Reference All commands require operator permission level 2.

/impostor possess good <player> [target] — Possess a player as a Kind Impostor /impostor possess bad <player> [target] — Possess a player as an Evil Impostor /impostor possess release <player> — Release a possessed player /impostor possess list — List all currently possessed players /impostor possess attack <player> — Force an Evil Impostor into kill mode immediately /impostor config <key> <value> — Modify any config value at runtime Key config parameters:

Key Default Description enabled true Master switch trigger_chance 0.2 Probability of triggering possession when conditions are met night_only true Only trigger at night isolation_distance 50 Distance from others required to trigger (blocks) min_isolation_time 1200 Minimum isolation time before trigger (ticks) max_isolation_time 3600 Maximum isolation time window (ticks) max_possessed 1 Max simultaneous possessions possession_cooldown 36000 Cooldown per player after release (ticks) instant_kill 1 Enable one-hit kill mode attack_damage 19 Damage per hit in kill phase voice_enabled true Enable voice mimicry debug_mode false Show AI state above player's head Anti-Cheat & Integrity The mod includes built-in safeguards:

AntiCheat: Detects and blocks abnormal movement packets from possessed players (threshold: 2-block delta per tick) IntegrityChecker: Verifies that core system classes have not been tampered with at startup StringObfuscator: Sensitive internal strings are obfuscated at compile time Compatibility Platform: Fabric 1.20.1 Java: 17+ Dependencies: Fabric API only Server-side only: No client mod required for basic functionality

中文

Impostor（伪人） 是一个面向 Minecraft Fabric 1.20.1 多人服务器的恐怖生存模组。它不生成新的怪物，而是悄悄附身在线玩家，将其变成由 AI 操控的傀儡——外表、动作、名字与真实玩家毫无二致。

与传统怪物模组不同，伪人完全在"玩家行为"的伪装下活动：进食、跟随、打怪、聊天、蹲下起身……让你无从分辨身边哪个"人"是真实的玩家，哪个是不该存在的东西。它的恐怖不在于你看见了什么，而在于你信任了谁。

两种伪人类型 Bad伪人（Bad Impostor） Bad伪人是捕食性实体。一旦附身玩家，它会悄悄观察、建立信任、然后发动致命一击。

行为阶段：

阶段 持续时间 描述 拟态期 ~5秒 立刻跟随目标，主动击杀附近敌对怪物，表现得像"队友" 判断期 5~8分钟（可配置） 在安全距离内跟随目标，随机切换行为：跟随、缓慢靠近、横向移动、蹲下起身、环顾四周，模仿真实玩家行为 伪装状态1 ~15秒 缓慢靠近目标，将自己的名字替换为伪造的玩家名 杀戮模式 最长30秒 全速追击，每0.75秒造成一次伤害（伤害值可配置）。30秒内未杀死目标则退入伪装状态2 伪装状态2 ~15秒 再次重复靠近流程，并开启攀爬墙壁能力 杀戮循环 无限 继续攻击，循环往复 连锁附身机制： Bad伪人成功杀死目标后，不会消失，而是：

悄悄将被杀玩家原地复活，恢复满血 立即对该玩家发动新一轮附身，变为新的Bad伪人 原伪人则解放 这意味着一个伪人可以在服务器中悄无声息地转移目标。

被攻击反应（随机触发）：

蹲起循环（35%）：反复蹲下起身，模拟惊慌的玩家 闪避（35%）：横向或后退移动 反击（10%）：立刻反打 逃跑（10%）：短暂逃离 冻结（5%）：完全静止，如同愣住 消失（5%）：瞬间释放，毫无痕迹

Good伪人（Good Impostor） Good伪人是被动游荡的实体，永远不攻击玩家。

行为特征：

跟随最近的玩家，保持一定距离 没有玩家时，自由游荡：随机行走、原地静止、环顾四周、蹲下起身、侧移，偶尔"挖矿"或"放置方块" 主动攻击附近敌对怪物，像一个沉默的护卫 永远不进入杀戮状态，指令也无法强制其攻击 Good伪人营造一种近乎"伴侣"般的存在感——感觉似乎友好，却从根本上不对劲。

自动触发条件 模组在后台持续监控玩家状态，满足以下全部条件时自动触发附身：

玩家已孤立（离所有其他玩家足够远）超过一定时间（默认60秒~180秒） 当前为夜晚（可配置，默认仅夜间触发） 随机触发概率通过（默认20%） 该玩家不在冷却期内（默认释放后30分钟冷却） 该玩家不在重生豁免期内（默认重生后60秒） 当前被附身玩家数未超过上限（默认1人） 寻路 AI 所有被附身玩家的移动均采用自写 AI 寻路引擎。原因是 Minecraft 内置寻路系统（PathNodeNavigator）只支持 MobEntity，无法用于 ServerPlayerEntity。

寻路特性：

支持8方向平移 + 上下跳跃 验证每个节点是否满足玩家碰撞体（2格高）的可通行条件 路径缓存15 tick，降低服务器开销 无路径时自动降级为直线移动 单次计算最多1500次迭代，防止服务器卡顿 语音系统 可选的语音模仿系统会录制玩家短暂的语音片段，并以扭曲、诡异的方式回放：

随机音调偏移 倒放（5%概率） 截断或循环重复 回放间隔：15~45秒（可配置） 聊天系统 被附身的玩家会偶尔在聊天栏发言以混入正常玩家：

被攻击时发送困惑/惊慌的消息（30%概率） 平时以极低频率发送随机消息（每tick 0.5%概率） 支持中英文双语（按玩家语言偏好自动切换） 客户端视觉效果 玩家被附身时，服务端会向客户端发送数据包，更新视觉状态：

可应用自定义皮肤覆盖（空皮肤材质路径可配置） 进入杀戮阶段时，名牌被替换为伪造的玩家名 解除附身后，所有视觉效果完全还原 指令参考 所有指令需要OP权限（等级2）。

/impostor possess good <玩家> [目标] — 以善灵伪人类型附身指定玩家 /impostor possess bad <玩家> [目标] — 以恶灵伪人类型附身指定玩家 /impostor possess release <玩家> — 解除指定玩家的附身状态 /impostor possess list — 列出当前所有被附身玩家 /impostor possess attack <玩家> — 强制恶灵伪人立即进入杀戮模式 /impostor config <参数> <值> — 运行时修改任意配置参数 常用配置参数：

参数名 默认值 说明 enabled true 总开关 trigger_chance 0.2 触发概率 night_only true 仅夜间触发 isolation_distance 50 孤立判定距离（方块） min_isolation_time 1200 最短孤立时间（tick） max_isolation_time 3600 最长孤立时间窗口（tick） max_possessed 1 最大同时附身数 possession_cooldown 36000 单玩家冷却时间（tick） instant_kill 1 开启秒杀模式 attack_damage 19 杀戮阶段单次伤害 voice_enabled true 启用语音模仿 debug_mode false 在玩家头顶显示AI状态 反作弊与完整性保护 模组内置多重安全机制：

AntiCheat（反作弊）：检测并阻断被附身玩家产生的异常移动数据包（阈值：每tick移动超过2格） IntegrityChecker（完整性校验）：启动时验证核心系统类是否被篡改 StringObfuscator（字符串混淆）：内部敏感字符串在编译期混淆处理 兼容性 平台：Fabric 1.20.1 Java 版本：17+ 依赖：仅需 Fabric API 纯服务端：客户端无需安装任何附加模组