If your talking about "Tabuu" you fight him at the end of subspace emissary.
Be warned it is quite hard.I had to do it 67 times.
After you beat the subspace emissary, you have to go back to the swamp and there is another door there for you somewhere go to the ruins to obtain wolf, after beating subspace emissary.
It's not. You can only face them in the Subspace Emissary or Boss Battles.
Subspace Emissary.
No
Its subspace emissary. :)
Sonic will appear during the final battle in the Subspace Emissary
Subspace Emissary
there are 35
you can`t.
She is. she is in 'THE SWAMP"
there is a seccret passage
On the fighters trophys in the Subspace Emissary.