New World Lovetopia Memento

Once upon a time there was a "big hole" between the other world and the human world, through which various otherworldly creatures flowed into the human world. The one-way "big hole" kept the otherworldly creatures in the human world, where they began to coexist with humans. The tribe of angels, unable to return to their original world, keeps searching for the "big hole to return to", but they reach a certain young man...?