Epigoni
In Greek mythology , the Epigoni or Epigonoi ( ; from , meaning "offspring" ) are the sons of the Argive heroes , the Seven against Thebes , who had fought and been killed in the first Theban war , the subject of the "Thebaid" , in which Polynices and his allies attacked Thebes because Polynices' brother , Eteocles , refused to give up the throne as promised . 
<triplet> Seven against Thebes <subj> Greek mythology <obj> from narrative universe <triplet> Polynices <subj> Eteocles <obj> sibling <triplet> Eteocles <subj> Polynices <obj> sibling