4) Use blades and traps to make your hits stronger. Use treasure cards if necessary.
5) Use a treasure card Humongo Frog to take out the minion and damage Krok at the same time. The frog is more powerful than your Sandstorm. You can buy them in the Bazaar.
6) Use team-up if you just can't get past this boss by yourself
I'd suggest leveling up a bit before your next attempt if it's really that difficult right now. That way, you'll be ready for the quests that follow, too. If patience isn't your thing, though, head to the Wizard City library and stock up on treasure cards.
It's also possible you just need some help for this one, and that's cool- I've been there. If you don't have irl friends that play, ask in the Commons or Bazaar if anyone is willing to battle him with you.
Okay, the Krokenkahmen shouldn't be too difficult as an adept sorcerer. Here's my thoughts:
Deck - Have your elemental shields in, place in a couple weakness, balance blades, heals and a couple hexes. You can add Lotus Swarm too as well as a Scorpion or two. You shouldn't need anything else (notice I didn't say any Myth Spells).
Gear - Get some adequate level 20+ school only gear from the Bazaar if you don't have any crowns to explore the various packs in the crown shop.
Wand - Try picking up the wand from the bazaar that adds an extra pip upon battle start (Wand of the Oasis). It's there!
Treasures - Buy a few enchants; Tough, Giant, etc. you think you may need.
Battle - Firstly, don't shield on the first turn, rather, use a weakness on the boss. If the minion uses a weakess on you, wand it off the next turn. Shield when the opponents seem to be stacking up. Use your balance blade and discard to enchant your sandstorm hit. A bladed enchanted sandstorm should severely hurt the boss and dispatch the minion.
Heal if necessary.
Finish the boss off with whatever means necessary. {Scorpion, Lotus Swarm etc.}