The Chosen Ones

You need to stand on the blue flame with Galeoth, just as you need to stand on the fire with Phodom and on the lightning with Fradz.

Where can I find the Black Merchant on ch. 7? I found it in my previous playthrough, but I've been patrolling the big market and the small market with my heroes for a long time now and no sign of him. I'ts the last thing I need for the chapter and, yes, it's night time.