Complex sentence: He then attempts to sacrifice Erza to reincarnate Zeref, killing their friend Simon in a duel against Natsu Dragneel, but is defeated after Natsu consumes Etherion's residual energy to achieve Dragon Force, and is seemingly killed following the tower's destruction.
Split into simpler sentences: He then attempts to sacrifice Erza to reincarnate Zeref, killing their friend Simon in a duel against Natsu Dragneel. He is defeated after Natsu consumes Etherion's residual energy to achieve Dragon Force, and is seemingly killed after the tower's destruction.