Amō is a young boy with messy neck-length black hair and narrow, grey-yellow eyes. His skin is pale with a light tan. He wears blue jeans, red shoes and a white hoodie.
According to Karasawa, his behavior is troublesome and could pose a potential liability for Border if publicly displayed. He seems to be a thorough person, going so far as to destroy a large portion of the Forbidden Zone when defeating trion Soldiers during the invasion. He also seems to enjoy challenges, and is bored by weak opponents.
He seems to have a good relationship with his former fellow S-rank agent. He fulfilled Jin's request without much complaint and was later seen enjoying some of Jin's rice crackers with a blissful look on his face after he finished in an anime-only scene.
- According to Ashihara, his design concept is an abandoned dog.
- In Japanese, his name Amō (天羽?), means "heaven's feather"; Tsuki (月?)) means "moon" and hiko (彦?) is a male noble (male version of hime) and it is also a common ending for boys' names.
- He likes water, hamburgers, chocolate, and fighting with strong opponents.