Mega Man
From Board 8 Wiki
Kills bosses and uses their power. Knows how to charge Atomic Fire, the Mega Buster, and a few other weapons.
Capcom has put Mega Man into many game series, and they build off each other by harnessing the power of sequels. The least successful series is the sports one (you think Battle and Chase is bad? Try Mega Man Soccer!).
A few idiots suggest that Mega Man's success can be blamed on the amnesia that all Capcom games generate. How else can Capcom sell the same game seven times over? But obviously it's because Mega Man > Ulti.
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