I could 2-shot the demons with my zweihander, so if you have a strong weapon and a bow you can pull them to you one at a time. Also, you can get Quelaag's sword witohut having to getting the chaos ember, so unless you really have a weapon in mind to upgrade into chaos I don't see why you'd want to go over there other than murdering a bunch of demons.
Speaking of that (I forget if I mentioned this...), on my supposed co-op character I was running around undead burg, but I was getting enough souls to level before I got to the boss almost constantly. This lead to me having a fairly decent enough amount of humanity with all the things I was repeatedly killing. Then, on a whim, I decided to go murder the black knight before the boss. Zweihander naturally did wonders staggering him, and he actually dropped a black knight sword.
Afterwards I sequence broke and killed Havel with the thing, went to the blacksmith, went to get the three firekeeper souls that you can get access to before any of the bosses (This is a mistake by the way, don't do it), got chloranthy ring, then when I finally decided to progress and kill the bridge taurus demon I one shotted him with a plunging attack from the black knight sword. That was pretty awesome, it's a shame the black knight weapons have such a silly power attack, otherwise I wouldn't mind using them so much.