Recs for cool action manga with multiple factions

[RisingC]

Looking for good action manga (shonen or seinen) with an emphasis on the relationships of a small or large size of characters/factions with varying motivations, causing them to team up or betray one another when the situation calls for it. Preferably featuring a protagonist that isn't too much of an insert character.

The sub genres don't matter to me either it can be sci-fi, fantasy, delinquents, etc as long it meets the prerequisites I established above.