ModNPC Class

Base class for creating custom NPCs, enemies, and bosses.

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Overview

The ModNPC class allows you to create custom non-player characters including friendly NPCs, enemies, and bosses with custom AI behaviors. This builds on concepts from ModItem, so review that first if you're new to tModLoader development.

Basic Enemy Example

using Terraria;
using Terraria.ID;
using Terraria.ModLoader;

namespace YourMod.NPCs
{
    public class ExampleEnemy : ModNPC
    {
        public override void SetStaticDefaults()
        {
            Main.npcFrameCount[Type] = 6; // Number of animation frames
        }

        public override void SetDefaults()
        {
            NPC.width = 40;
            NPC.height = 40;
            NPC.damage = 20;
            NPC.defense = 10;
            NPC.lifeMax = 100;
            NPC.HitSound = SoundID.NPCHit1;
            NPC.DeathSound = SoundID.NPCDeath1;
            NPC.value = 100f; // Money dropped
            NPC.knockBackResist = 0.5f;
            NPC.aiStyle = NPCAIStyleID.Fighter; // Zombie-like AI
        }

        public override float SpawnChance(NPCSpawnInfo spawnInfo)
        {
            return SpawnCondition.OverworldNightMonster.Chance * 0.1f;
        }
    }
}

Creating a Boss

Bosses require more complex setup with custom AI:

public class ExampleBoss : ModNPC
{
    public override void SetStaticDefaults()
    {
        Main.npcFrameCount[Type] = 4;
        NPCID.Sets.BossBestiaryPriority.Add(Type);
    }

    public override void SetDefaults()
    {
        NPC.width = 100;
        NPC.height = 100;
        NPC.damage = 40;
        NPC.defense = 15;
        NPC.lifeMax = 5000;
        NPC.boss = true; // Mark as boss
        NPC.npcSlots = 10f;
        NPC.value = Item.buyPrice(gold: 5);
        NPC.knockBackResist = 0f; // Immune to knockback
        NPC.noGravity = true; // Flies
        NPC.noTileCollide = true;
        Music = MusicID.Boss1;
    }

    public override void AI()
    {
        // Custom AI code here
    }
}

NPC Properties Guide

aiStyle

Built-in AI patterns:

  • • Fighter (zombie-like)
  • • Flying (bat-like)
  • • Worm (segmented)
  • • Custom (write your own)

boss

Mark NPC as boss:

  • • Shows health bar
  • • Prevents despawning
  • • Boss music plays
  • • Special death effects

Learn More

For complete ModNPC documentation with AI examples:

View Full ModNPC Documentation

For complete ModNPC documentation:

View Full Documentation