want to have a dps hero. which one should i do? is there something like the best dps hero?

Best dps hero, well not really, it's a matter of personal taste I'd say.

Huntress,Ranger,Monk,Barbarian and Jester all fit the role well.

Depends if you want a ranged or melee one basically.

Monk, He will deal dmg as dps, he can have tower & hero boost.
He is just loved as dps in multiplayer
for pure dps i would say huntress.

Monk is best, even pure DPS options you must choose Monk or Barb if you want the best, and barbs only real claim to the throne in my opinion is hawk stance or w/e since it can 1 shot pretty much anything in the game w/ top end game gear.

Monk has the benefit of his boosts at least helping other teammates even if they are only temporary, which is helpful period.