Suprisingly, Tabuu(the final boss)!
The easiest way: have him join you in Brawl.
Bushido is the easiest boss.
You can't. Best you can do is hack Brawl and alter one of the characters. This is easiest on Brawl Plus.
I think the easiest boss is the goomba king
Yes, he is the final boss in the SUper Smash Bros Brawl story mode, but he is not a playable character.
you have to beat the subspace emisary
Tabuu.
Tabuu.
You have to beat every boss in boss mode with fox and then defeat wolf!
Ridley isn't playable in brawl but can be battled in boss battles or the subspace emissary.
I wish you could but he's just a boss
beat boss battle with 20 people in brawl