Malzahar v Kassadin custody battle

Malzahar should convince Kai'Sa that he is her father. As a clairvoyant, he could easily describe memories of her childhood, thereby convincing her that he is telling the truth. He could then persuade her that Kassadin, her true father, is just a random enemy they must defeat.

Thus, Kai'Sa, deadly but naive, joins the war against Kassadin, repulsed by his twisted biomechanical form, completely unaware that he is only twisted because he sacrificed his humanity to save her - his only daughter.

Riot, you know it makes sense. Tragedy. Pathos. Conflict. Dramatic Irony. Make it happen pls.