Io is a Holland Lop rabbit with long-furred, drooping ears and a short rabbit tail. He has purple Jewel Eyes made of cordierites. He wears a purple ribbon bowtie on his neck.

In Jewelpet, Io is one of the Jewel Eight. Dian brainwashes him into using his inverted power to tire humans out. Rinko's group reclaims him through the Jewel Games.

In Jewelpet Kira Deco, Io joins Coal together with Opal, whom he proudly serves, to help Coal obtain the Deco Stones for the Decoranain.

He is in the background in the other seasons.