Star Spirit

If you want to put it in rank, the Star Spirits is at the top of three races, the two other races are equal to each other. This is not a problem of fighting prowess, but because the Star Spirits and the origin of humanity are completely unrelated, thus their birth is inevitable. The above are just unknown worlds. Hence, to completely kill a Star Spirit, unless you have a secret technique that can bring total annihilation on infinite worlds, or it would be impossible otherwise.