Complex sentence: Though defeated, Zera swore that she would be back and she would never stop trying to kill Spawn, who decapitated her and brought her head in front of God Himself, to whom she apologized for her failure.
Split into simpler sentences: Though defeated, Zera swore that she would be back and she would never stop trying to kill Spawn. Then Spawn decapitated her and brought her head in front of God himself, to whom she apologized for her failure.