Kirio

The youngest but also the strongest of the four Chosen of the Beast Spear. He wields the Elzaar Scythe and is accompanied by a monster partner call Kuin.

It turns out that he is the created by Kyoura and Towako from a human child to wield the Elzaar Scythe. Later he is taken in and lives with the Inoue family.

(Source: Wikipedia)