What if his OTL wife marries Dusan's son and Louis of Hungary dies heirless before Casimir III of Poland dies, if Casimir of Pomerania takes the throne, I know that Casimir of Pomerania is considered barren or impotent because he did not sire any heirs which means Poland will be ruled by Sigismund, how would Sigismund I of Poland act and would he still ally with the Teutons like in OTL?