In Dark Souls, I have just defeated Ornstein and Smough and acquired the Lordvessel. Now, if I remember correctly, you can give this to Kingseeker Frampt, but that will make it impossible to join the Darkwraith covenant. I'd rather give it to Darkstalker Kaathe. I have never played past this point before so I only know about Kaathe from the Dark Souls Wikis.
I have also just bought the Add-on Artorias of the Abyss and have read that the Great Grey Wolf Sif appears as a summonable NPC in a new area, as long as he wasn't killed before, which also changes the cutscene before the fight. As requirements to access the DLC I have read that you have to kill some crystal golem in the Darkroot Basin and to place the Lordvessel.
But, to get to Kaathe, if I understood this correctly, you have to kill Sif to get a ring to walk the Abyss where Kaathe apparently is. So if I want to access the DLC before getting to Sif, I would have to give it to Frampt, right?
The only other option I could imagine is to place the Lordvessel by jumping down the hole where Frampt is, whithout waking him up, but I read that that makes him angry somehow. Also, can I still help Kaathe after doing that?
Long story short: I want to join the Darkwraith, but also access the DLC and have Sif there before killing him to walk the Abyss. Is this possible?