you find tree rex's soul gem in molkin mountain just before the arena battle, but you will need to push a block down from the part before
you find sunburns soul gem in his adventure packs level
Darklight krypt is where you find sunburns soul gem
by a tree and next 2 the dork
you find the soul gem in darkwater cove but i dont know the exact place in the level
Whirlwind's soul gem is on Chapter 17, Creepy Citadel. After the little goblin puzzle, there is a platform with two Gargantulas. Defeat them to open the gate and get the soul gem. Hope this helped.
it is in precous pastures
You find it on Cadavourus Crypt
as well as Terrafin, sunburn and ghost roaster you find it in his adventure packs level
GET soul gem and unlock the soul gems upgrade
dragons peak on 1st pounce pads
dark light krypt
in the level empire of ice but you have to buy it