As a test subject in the same Weapon X program that had previously given Wolverine his adamantium claws and skeleton, Wade Wilson received a healing factor that prevented his cancer from killing him.Marvel Source
Wade soon escaped the program and became a freelance mercenary using the name Deadpool, working for various criminal organizations. At times he has teamed up with heroes as well, but these attempts at "being a good guy" rarely stick for long.
Wade is mentally unstable, though whether this is a normal state or is caused by his constant state of hyper-regeneration is unknown. One side effect of his mental state is the belief that he is not a real person but actually a character in a comic book.
Use all dodge% affix on your costume and get as much dodge as you can on your items. You're not a tank so you need the dodge in melee to be useful. Drop Foot Gougers, Stink Bomb, then Slice 'n' Dice away while hitting Get Better Faster whenever you need. If you are in a tough area and the mobs don't die really fast then go ahed and use Lil' Deadpool as well to distract some of them off you. If the mobs die too fast don't waste your time with it. Use Teleport to get away when you find yourself taking on more than you can heal.