I just realized I was thinking of darkness as it was in 3.0 (when you couldn't see anything). After having re-read the spell. It seems like it would be better to use a fog cloud. There is also a least invocation that copies that spell, so it would be fairly easy. Is there any way to make it so that the eldritch blast doesn't rely on Dex? Even as a ranged touch attack, My BAB is too low (+3) to give me a significant chance of hitting. I mean I have a -2 DEX mod, so it seems like Ranged attacks are kind of out of the question. Plus I don't want to be forced to split my feat choices between ranged and melee because I don't really get enough of them as it is. Also Eldritch Blast never really impressed me that much; unless you go straight warlock, the damage is too small. Maybe if I used the Hellfire Warlock PrC (Fiendish Codex 2 pg. 90). That requires a minimum of 6 levels in warlock though, unless there is some fancy way to get lesser invocations earlier than that. Plus the CON damage would be kind of painful. I guess wands/scrolls of restoration would be in order; Use Magic Device is a lifesaver.
Basically I'm wondering if a whole level is worth a permanent fog cloud. I'm erring on yes, especially because a level of warlock will buff my Will save, which is always helpful for a tank. I cant even count the number of times one of my characters has been taken out of the fight instantly, or, even worse, turned against the party.
Thanks for all your help weenog. I would never have thought to look at warlocks.
Also, SorO_Lost, I think i'm heading away from using darkness effects. I thought it was much better than it actually was, and so am going more with fog cloud and the like.
This brings up an interesting question though: with faceless hate, i have lost my face. Thus, how do I eat? Do I need to breathe? In the disease description it says that affected creatures lose scent, so I assume I can't breathe anymore. So maybe I should get some sort of permanentized cloudkill cast on me?