gistfile1.cs

class MurasaPyromancer : CreatureCard, IAlly, IEventHandler<CreaterEntersBattlefield>
{
	public MurasaPyromancer()
	{
		Name = "Murasa Pyromancer";
		ManaCost = ManaCost.Create(red: 2, collorless: 4);
		Description = "Whenever Murasa Pyromancer or another Ally enters the battlefield under your control, you may have Murasa Pyromancer deal damage to target creature equal to the number of Allies you control.";
	}
	
	public void Handle(CreaterEntersBattlefield @event)
	{
		var allyCount = Owner.CreaturesUnderControl.Count(c => typeof(IAlly).IsAssignableFrom(c));
		var tagetCreature = Engine.TargetCreature();
		
		targetCreature.TakeDamage(allyCount);
	}
}