It's been a long time since we took a look at Prime World, Nival's castle-building MOBA. You should definitely check out Hamza's interview with the developer from 2011, though, because it all takes place on a bouncy castle.
Prime World has been around for a while in Russia, but the English version has only just entered closed beta. You can sign up now for an early look at its MOBA combat, persistent RPG heroes, and castle construction. Or you could just check out the inadvertently hilarious trailer.