I get quest for Foulgaze and Nightside after finishing Colossus Blvd. Of course, I've done ALL the quests up to that point. Finished Find The Smiths, the special magical outfit from Gloria Krendell, etc. - even if the quest itself doesn't seem to have anything to do with the main story line.
Ok I am on mooshu right now so i know how to get past wizard city. you need to complete unicorn way, triton ave., firecat alley, cyclops ln., then talk to merle ambrose. he will give you 2 quests. one for foulgaze and one for collosus blvd., the storyline goes on by the foulgaze. you don't have to do collosus blvd. you need to defeat foulgaze, talk to merle ambrose, he will give you a quest to go to stormdrain tower. you need to defeat lord nightshade who is in the tower, and after you defeat him, talk to merle ambrose and he will give you key to the spiral portal to krokotopia. he will also give you a quest for nightside Happy Questing!
*Sigh* I don't remember when I got that quest. But I was a low level, like 15 or 20, I don't remember. LOL. But you have to beat WC and THEN go back to the Headmaster and go get the quest. I think. O_O