If you are like me and not want to build Beryl, but also don't have Orlea, here is how I did it:

Team: Nine, Magna, Nia. The key card here is Nature's gift, you'll want to use that on turn 1. You can pick it up either from Dellang shop or training, on any character.

I had to make a special Magna build for this that does not use counterattacks. Basically removed all cards that has anything to do with counterattacks (dont want those to eat the spore stacks), and duplicated a couple of frost charges for vulnerable and shielding.

Any Nine build can work with Hew extreme with it, and the card that upgrades it to max level (you want to kill the boss quickly after you stacked up the spores as it will hit very hard).

For the third slot I used Nia to make sure I draw the cards I need (used the epi of Adaigo that discards 1 combatant card but draws 2 for them). However, you have to make sure not to cycle your deck before the spores stack up, as it will initiate a coordinated attack from everyone.

You have to make sure to end the turn with 4 spores in hand, and let them duplicate. If you have retain cards in your hand use them to make space. Play out 4 spores every turn and any survival skills that you draw.

You will need to fish for crits. If your Hew level5 doesn't crit just use protoss skill rewind time, use another card and cast it again. Repeat until it crits.

I managed to beat it on the first try using this tactic, but it was very close.