Schmeiser said:
Dark souls 2 coming soon to PC so i better slay tom and fuckin jerry soon
Assuming you're talking about Smough/Ornstein and not the kings or something, playing them in heavy armor with high lightning resist and just mowing Smough down with pyromancy is the easy-mode solution. They're weak to fire, their heavy hits have large wind-up time so you can amble out of the way even under heavy-ish load, and Orn's lighting attacks are almost entirely lightning damage so you can soak it with focused armor even if he's too fast for you, then chip him down the usual way once his buddy's dead.
... or i guess you can just summon a friend in if you're REALLY feeling lazy.
EDIT: This isn't that unusual, the bosses in DS are designed very intentionally to be weaker to some builds than others, usually to the extent that you have to pick one and just deal with the fact that there are going to be things that are harder for you.
(You've got a good chunk of the game left to go after them, by the way. The four kings are the opposite, they're still multi-target annoyance but long-range magic and high dex/mobility are easier than armor/pyro... mainly because you'll run out of pyro long before they go down, but they also have good fire resist.)