Play your minions. Play their minions (if you’re lucky, ones that synergize). Deal with their minions through your face (you’ve got enough healing) and cheap removal spells.

LET’S JUST GO THROUGH THE CARDS BECAUSE I’M NOT GOOD AT THIS.

Bloodtear Alchemist

You know what this does.

Azure Herald + Healing Mystic

You’ll often be going face or clearing minions, and Mindlathe makes both players want to hurt you.

Bound Tormentor

Card advantage, tempo off the cheap plays. (Theft method #1.)

Wild Tahr + Thunderhorn

Exactly why you’re running this zoo is anyone’s guess, but they’re good minions, they make good use of Daemonic Lure, and… opponents often want to get rid of them for that brief moment before you play Nether Summoning? They influence opponent positioning? EDIT: Maybe they’re there to make the enemy General have second thoughts about staying in your face to damage your Mindlathe? Good removal bait to clear the way for Reaper? (Edit: As noted above somewhere, these were later removed for Spelljammer and Vorpal Reaver.)

Desolator

More healing. Your answer to artifacts? Emergency late-game wincon?

Reaper of the Nine Moons

It can be removal or burn and it’s good at dying  into Nether Summoning. (Theft method #2.)

Mindlathe

Whatever they’ve just summoned will hurt them as much as it hurts you. If hitting both Generals won’t kill the minion, be sure you have a way to do the necessary additional damage before or after or can afford to spend a Punish. Daemonic Lure works well with this (especially for Frenzy minions). You can use Healing Mystic to bring an enemy minion back to 3+ health if necessary. (Theft method #3.)

Demonic Conversion

Very easily afforded if you’re playing something you got off Bound Tormentor this turn. (Theft method #4.)

Punish

You’re Cassyva, you play Punish. Simple as that. Pings other than your BBS include Bloodtear, Lure, and Breath of the Unborn.

Breath of the Unborn

AoE is always good to have. This can get ridiculous value sometimes.

Nether Summoning

Guess who’s back, back again… Revive removed minions, favorably undo trades,  or kill and steal enemies.  (Theft method #5.)

As Jeff Kornberg would have it, all in all, this deck is a blast to play.