He is mostly useful in a JO Astaroth meme deck.
The idea is that you drop a Dragonclaw Pendant at some point in the game and, after that, as soon as possible (before turn 10 so the enemy can't reply with a Bahamut) drop Dread Sea Queen, Prince of Darkness, Python (in that order).
The result is that you have more than 20 damage on board, so the enemy has to address that, and the next turn you are guaranteed to draw Astaroth (as Python banishes all other cards from the Apocalypse Deck) for an instant kill spell (with Dragonclaw Pendant on the board it deals damage exactly equal to the enemy leader's health rather than 1 less), giving you a win-win situation unless the enemy has immediate lethal.
There should be a few other counters to that aside from Bahamut or immediate lethal. I think Earth Rune may have one or two options to deal with it, depending on the situation, which would then result in you decking out in the end. And if Rune, for some reason, decides to play a card that forces you to draw... you're dead. Not likely to occur, but that's something that can potentially happen. It's a good combo, though, since the only real threats are going to be Bahamut or getting killed outright with whatever the opponent already had on hand to finish you.