you could give them the ultimatum of ither joining him or destroy the universe.

i say you make evry avenger his subordinate as the plot for marvel is in the bin i mean he could use tony and dr baner as his engeneers thor as his general loki and dr strange as his magic division chiefs black widow as his spie network captain america as his consultant or somthing clint idk make him somthing captain marvel to idk i mean you don't have to kill them break them give them a ultimatum as he needs subordinates .