I think the card has alot of potential to be abused in priest shadow word pain pop chest instant treasure. Few other things could be used with it to set off the chest instantly that are 2 mana or less that could be used in priest. I think it has potential to be very good in priest. or anything where you can play marin and pop the chest in the same turn the resulting treasure is good regardless worst think you could pull is the golden kobold. I think this has alot of potential for a highlander like priest build.
Crazed Alchemist was already a decent tech card. Why is every comment suggesting this being ignored? No damage soak or waste of removal. Also great vs. Shamans, Doomsayers, or trading into a high health taunt. If not running Priest, I will certainly be using an Alchemist or two if Marin somehow ends up playable.
Not only can you hardly break the chest the turn you summon it (unless you're already winning, in which case you should go for lethal), but the rewards are utterly RNG and many of them with very bad downsides.
The body is just bad for its cost, not even taunt to protect you (unlike The Lich King).
Possibly worse than unplayable and it's not even a famous lore character...
You could have fun trying like mill rogue alchemist style deck with like shadow step pop the marin pop the chest with the alchemist if you could land a shadow step with the draw fill your hand you could litterly load the setup to go off every turn for 6 mana shadow step marin shadow step alchemist play both next turn for 6 mana and repeat.
Or just toss him in a standard priest and pop it off turn 10 before any defense against it can be made using Marin + Shadowword pain or Crazed Alchemist to get an instant 3 cost tresure card that basically non of them are ultimately indefinately mad though the golden kobold is probably the worst of the 4 tresures.
So far I personally thing its good or playable at worst even if you dont see alot of it I think it will see some play if it doesnt see alot of play even if its kind of just a tech for highlander. I mean the discover treasure alone for a legendary Lyra/Velen are both priest card legendarys which do have a higher ratio of being discovered which could out right win the game in highlander priest...3 mana double velen in high lander priest makes a 20 damage mind blast.