To even have a chance at this NPC for farming status you need:

1. Beat 30 NPCs to unlock 2 stars.

2. I would say about a 53 card minimum.

20 cards in your deck are 1 star cards.
17 cards are 2 star, so you want to at least get about every 2 star card out there.

I know people are upset at Kharhaz's tone and rightfully so, but there is strategy to the random just like all the other npcs.

RNG is involved, but you want to push the odd in your favor by getting 53 cards, you so you definitely need to pick up those 2 star cards ASAP.

The strategy often involves 2 ways but all of them need to have the end result of Odin being played up top so he does the least amount of "damage"

You can follow the strat explained, but my strategy involved baiting the NPC by placing a very low card in the middle. Cobelyn, Mandragora etc...

I think he should have A cards in his deck because right now he has a very pointless Fallen Ace rule that has no bearing on his deck.