Россиу Адай (ロシウ・アダイ, Roshiu Adai) — cирота, живший в деревне, где могло выжить всего пятьдесят человек. Самый этически сложный персонаж, его мать оказалась 51-м жителем и была принесена в жертву. Рационален, способен принимать жестокие решения, когда это необходимо, подавляя свои эмоции. После свержения Спирального короля стал вице-президентом (иначе — генеральным секретарём), а затем и политическим лидером Земли.
In part one of the series, Rossiu has slightly long black hair pulled back in a pony tail with a bang on the right side of his face. One might describe his head as being a little melonish and too large for his body, a feature that prompted Kamina to give him the nickname "Forehead Boy". He has thick black eyebrows and black eyes. For the entire first part of the series he is seen wearing the modest religious garb of Adai village. His clothing includes loose white-blue pants tucked into tan boots and a white poncho/cloak with a high collar and two rectangular blue markings on the left side. He often wears a flat and sullen expression and rarely shows emotions other than anger or frustration, smiling once or twice.
Rossiu's general appearance changes a bit in part two of the series,most of the changes being that of clothing. The color scheme is the same, but he now has a more commanding appearance, largely due to his military-like clothing. He wears a white coat that goes down close to his ankles. He wears white pants and boots, and two orange shoulder pads, the left one having a darker orange stripe down the middle. There are two orange stars on the left side of his chest. He still has the same pony tail hair, only slightly longer. Rossiu also seems to have grown into his melon forehead. In this part of the series, his expression remains as blank as ever, showing actual emotion even less than usual. However, he does seem to have a slight smirk when exhibiting his stolen powers.
- The name that Kamina refers to him as in the primary series "dekosuke" is a remark regarding the large size of Rossiu's forehead. The name "dekosuke" roughly means "big forehead". In the dub, Kamina nicknames him "Forehead Boy."