Damn. Brother, congrats, that's an amazing pull! This is my opinion and NOT financial advice; that said, I will hold on to that card. First, the DO cards are undervalued because they are still up for sale and can be balanced until they are locked. When cards are fused, it makes the card rarer, which in turn pushes the price up (Core Cards have a different outlook, although, with fusing, it will push card pries). Another factor yet to be implemented is earning Gods for higher shine decks, which again pushes higher shine card prices. I hope this helped; good luck with the weekend ranked—also, kudos for being a nature one-trick.
RE: Diamond Thunder Caller, Should I Keep It?