So, as the first epic quest in the game, I was stuck at it for quite a while. However, the way to beat it is extremely easy if you're level 12 . I would still recommend level 15 to make it less subject to RNG though.

Team Building

What you will need:

• Taunt Spammer

Recommended Choices:

• Stone Fist (Can Reduce his Damage and Tankiness, Taunt mitigates a lot of RNG, Easily Farmable)

• Healer

Recommended Choices:

• Nub Nub (Good Heal Over Time, ATK/DEF buff for team, increases CRIT to make the clear faster, Element Advantage),

• Yasmin Bloom (Team and Single Target Heal, More Healing than Nub Nub, Easily farmable)

• Damage Dealer

Recommended Choices:

• Willow Swift (Able to Spam both abilities to do amazing DPS, Element Advantage, Able to Dodge Snowball if you mistime taunt, Easily Farmable)

When Travelling to the boss, make sure to spam taunt and heals to keep your health topped up. On the last stage, start watching your cooldowns.

When you get to the boss, spam taunt and heals throughout the fight. Try to time it so the turn your taunt is down is the turn that he summons his boulders. Focus the Ice Shard, not the boulder, as the ice shard does 90%-100% of Yasmin's Health, while the boulder does maybe 60%.

TL;DR: Spam Taunt and Heal, focus down the spike when it spawns.

Good Luck!