It’s my Opus VII community spoiler!
Checking out Kolka at a glance, he’s a straight up faster version of Mog (MOBIUS), and gives you a bit of name variance if you need it for your backup line, with the downside of not being able to self-break to clear up backup space.
To his advantage, Kolka can search a staggering amount of good cards, Earth is an element renowned for having sturdy, powerful forwards (Cecil, Dadaluma and Wol spring to mind immediately, but you can also search for things like PSICOM Enforcer or Raubahn if you need to toolbox removal. You could even search out the new Noctis to turn the game around when you’re on 6 points of damage!)
As he’s a searcher, there’s not a huge amount to write about him, as his real strength comes from what he can search rather than what he does himself. As I do with Merlwyb in Mono Water & Ysayle in Mono Ice, I’d tentatively try Kolka as a 1-of just to bring the consistency of your deck up a bit, especially as he’s a soft 2 CP card, which doesn’t even make him that bad to play early.
I’m rating him a “Blow an Airhorn and search Dadaluma” out of 10.