A member of Atheos initially with a band around his head.
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He is not very deeply informed about Atheos's goal but proceeds to work there, as his mother is being treated at Atheos's hospital in return for his job. He has had previous experience with Chimairas, the first one he meets being Nana. Unaware of what she really is, she tells him that she is being chased and he vows to protect her, though he goes back on that promise when she awakens as a Chimaira and he shoots her. Deeply passionate in what he does, he supports Aiko from the moment he meets her, seeing a bit of resemblance to Nana. However this passionate support changes into protectiveness and finally to love. Sudo is always wanting to see her smile, making a promise with her just before his death. He is always there for her during her missions and finally there to block her from a rain of bullets. He seemingly attempts to kiss her before falling limp in her arms once more but appears again when she wakes up near death and ruffles her hair.
