8 X-Men Who Became Avengers
5. Sunspot
Roberto Da Costa, much like his best friend Cannonball, began as a student and eventual member of the New Mutants. Sunspot has a more carefree approach to life which could be due to his enormous wealth, which would prove to be a powerful asset when he eventually got his Avengers membership.
Roberto received his membership at the same time as Cannonball and was taken into space to help the Avengers defeat the Builders during the Infinity story arc.
Sunspot later used his wealth to perform a hostile takeover of the evil organisation A.I.M. and re-purposed them to provide scientific research and logistic assistance to both the Avengers and S.H.I.E.L.D.
Roberto then took the name "Citizen V" and lead his own contingent of the Avengers named the U.S.Avengers, working alongside the US government to protect America from potential threats. He has recently given up his roles as Director of A.I.M. and leader of the U.S.Avengers after his carefree attitude put him at odds with representatives of the White House.