Little is known about the figure known as Deadpool.
Morph knew about Deadpool. He morphed into the figure in order to taunt Wolverine, who tracked him to an underground mine.
When Xavier's dark side came out, he used the image of Deadpool to taunt Wolverine.
The character of Deadpool never actually appeared himself. He only appeared in memories and when Morph transformed. Even then, he is never named.
In the Comics
His name is Wade Wilson.
While not technically a mutant, got powers from Weapon X that include teleportation and a much more advanced healing factor than Wolverine's.
Modeled his costume after Spider-Man.
Knows he is in a comic book and breaks the fourth wall.
Has teamed up with Cable.