Complex sentence: Upon Allelujah's return he later consoles her with his reasons for fighting and asks Sumeragi what her reason is now for fighting after a battle and much thought Sumeragi decides to officially return to Celestial Being.
Split into simpler sentences: Upon Allelujah's return, he consoles her with his reasons for fighting and asks Sumeragi what her reason is for fighting now. After a later battle and much thought, Sumeragi decides to officially return to Celestial Being.