Ragnarok Odyssey Ace has collaborations with over a dozen games. That’s why Ragnarok Odyssey Ace has Gravity Rush costumes in it, but not all of the crossovers are within Ragnarok Odyssey Ace.
This video shows a Domovoi, one of the monsters from Ragnarok Odyssey Ace, in Emil Chronicle Online, an online RPG from GungHo. Princess Punt is kind of like an Angry Birds style game and it will have a special Ragnarok Odyssey Ace level where players can kick knights at Hrungnir, one of the giants in the PlayStation Vita game. Hrungnir will also show up in Puzzle & Dragons as a boss character for players to fight in the smartphone game.