Okay, completed costumes quests… so, yesterday…
Get 8xpull with keys, I only miss Gormek and Kelile costume from 4* heroes, and what I really want is Gormek.
8xpull keys: zonk,… all dups…
And today,… I would try to fill the cests, and try…
2xpull with keys: zonk… all dups.
And one more 1xpull with gems… and…
Finally…
I would max the costume, emblems and maybe put LB on him, I already LB Scarlett, so he is my next 2nd LB target.
Congrats for your chaos army upgrade… 
Yes, that is one of the reason I really want to chase Gormek.
Here is some of how useful Gormek is:
Goodluck everyone!