How can i add an enchantment that 1 shots to certain mobs?

So, I am adding a custom enchantment to my plugin. This is my first time ever adding a CE. Can someone tell me the events or the code it self i am going to need?
(i registered it/coded the wrapper all i need is events and increase the damage)
Heres the code:
//Main.java
package me.Alqkaria.orphan;

import org.bukkit.plugin.java.JavaPlugin;
import org.bukkit.event.Listener;
public class Main extends JavaPlugin implements Listener{
@Override
public void onEnable() {
OrphanEnchants.register();

this.getServer().getPluginManager().registerEvents(this, this);
}
@Override
public void onDisable() {

}

}

 

EntityDamageByEntityEvent

You check if the damager is a player, and if yes, check if the item they are holding has the specific enchantment.

 

Check when projectile lands, if it is arrow then check the mob which it hurted and if its your specific type then set it's health to 0