Kaos

Kaos is an Trans-Fusion creature, that Humans create them in an experiment, which have forgot to give Kaos a specific race to them, and end up chaos happened in that universe, and fell onto Earth with a living plushie which named Plushie, as simple as it.

An adopted child by a demon, that live with a living mutation plushie, that greets others races on the planet named "Isekai" which the planet contains multiverse without requirements to travel.