DM Entity Possession System

[FirebrickRed]

Summary

Allow DMs to "possess" entities and control them directly - walking in their shoes, speaking as them, and accessing their inventory. Essential for immersive roleplay and dynamic NPC control.

Phase: 4 - DM Tools
Systems: DM Tools, Entity System

Prerequisites

• Unified Entity System Foundation #72 - Unified Entity System Foundation
• Entity Spawning Commands (DM-Only) #73 - Entity Spawning Commands
• Entity Stat Block Display #74 - Stat Block Display

Goals

• Right-click entity to possess/unpossess
• Player becomes invisible, entity follows player movement
• Special "DM Wand" item for quick possession (optional alternative to right-click)
• Access entity inventory and stat block while possessed
• Sneak to exit possession
• Prevent non-DM players from possessing

Cleanup Tasks

• Delete listeners/NpcListener.java - Replace with new possession system using DndEntityInstance
• Delete CustomNPCs/NpcManager.java - Replaced by EntityLoader
• Delete CustomNPCs/NpcData.java - Replaced by DndEntity
• Delete CustomNPCs/Hadozee.java - Example replaced by generic entity spawning

User Experience

# DM right-clicks on town guard
> "You are now possessing Marcus the Brave"
> Player becomes invisible
> Guard armor stand follows player movement

# DM opens inventory while possessing
> Shows entity stat block + inventory (Issue #74 format)

# DM right-clicks item (future: shop commands)
> Can adjust prices, manage shop inventory

# DM sneaks
> "You are no longer possessing Marcus the Brave"
> Player visible again, guard stays at last position

Technical Details

• Permission check: jkvtt.dm before allowing possession
• Invisibility: PotionEffect.INVISIBILITY while possessing
• Movement sync: BukkitRunnable every tick teleports ArmorStand to player location
• Inventory access: Show stat block from DndEntityInstance template
• State tracking: Map<UUID, DndEntityInstance> for active possessions

DM Wand (Optional Enhancement)

• Blaze rod with NBT tag "dm_wand"
• Right-click entity to possess (alternative to direct right-click)
• Shift-right-click in air to list nearby entities
• Easier for DMs to avoid accidental interactions

Next Steps

After completing this issue, tackle:

• Entity Group Management System #79: Group Management (possess and move entity groups)
• Shop Price Adjustment System (DM-Only) #76: Price Adjustment (adjust shop prices while possessing merchants)

Related Issues

• Unified Entity System Foundation #72 - Unified Entity System Foundation (prerequisite)
• Entity Spawning Commands (DM-Only) #73 - Entity Spawning Commands (prerequisite)
• Entity Stat Block Display #74 - Entity Stat Block Display (prerequisite)
• Entity Group Management System #79 - Entity Group Management
• Shop Price Adjustment System (DM-Only) #76 - Shop Price Adjustment