Originally posted by Endless Mike
They were both seriously beat up and weakened at the time, Fenris didn't give him any extra power, just inhabited his body
Plus Michael was trying to get Lucifer to snap out of the mindrape, not fight him, so your claim that Lucifer is greater than Michael is incongruous.
Well... Michael, Lucifer, and Gabriel were Yahweh's first 3 creations and they each had their own respective roles in shaping the universe. While Michael is more powerful and was originally intended to be Yahweh's successor for the universe, Lucifer has his wits and fulfilled the plan by being rebellious. Yahweh even states the slightest doubt he had in his plan was which one he would choose as his successor. The power that each character possesses doesn't necessarily equate to level of treatment they receive.
Michael's name implies it (Demiurgos- second only to God). Hell Lucifer, who's extremely cocky and arrogant, offers Michael a partnership in ruling his creation, almost explicitly recognizing him as an equal. Also when an angry Michael vows he'll destroy anything because there is nothing he loves enough to spare, Lucifer doesn't say something witty implying he is more powerful like he always does, he simply receives the statement.