User blog comment:ARagingKid/ARK's Thematic Thumbnail Contests/@comment-27416494-20180325201149/@comment-27416494-20180325203711

Shepard's biotic powers are completely optional, or at least entirely dependant on the character class you pick at the start of the game. The default Soldier class (which is what Screwattack would most likely use if Shepard ever entered DB) has no Biotic abilities to speak of.

Chief admittedly lies in a bit fo a gray area, but I wouldn't necessarily count genetic enhancements as superpowers. I kind of see Chief in a similar light to Captain America in this situation.