How do I free Shakkik?

I solved the murder, but noone seems to be interested... Arashad says he doesn't want anything to do with it.
Kench and Urshak (the couple) lie dead (I got Urshak' soul).

Do I need to find that Sura warrior?

Have you talked to the merchants yet? Takes some running back and forth between the different merchants, but that should allow you to progress.