NPC.cs

using System;
using UnityEngine;

public class NPC : MonoBehaviour
{
    public event Action OnNPCDied = delegate { };

    internal void TakeDamage(int amount)
    {
        GetComponent<Health>().TakeDamage(amount);

        if (GetComponent<Health>().CurrentHpPctent <= 0)
            Die();
    }

    private void Die()
    {
        OnNPCDied();
        GameObject.Destroy(this.gameObject);
    }
}