// When Kiri-Onna enters the battlefield, return target creature to its owner's hand.
Ability ability = new EntersBattlefieldTriggeredAbility(new ReturnToHandTargetEffect(), false);
ability.addTarget(new TargetCreaturePermanent());
this.addAbility(ability);
// Whenever you cast a Spirit or Arcane spell, you may return Kiri-Onna to its owner's hand.
this.addAbility(new SpellCastControllerTriggeredAbility(new ReturnToHandSourceEffect(true), filter, true));
}