Cyan is a middle-aged warrior with a long dark hair in a ponytail, and a short mustache. He wears blue armor in his pre-smartphone version in-game sprites, and brown armor in his Yoshitaka Amano artworks and in the smartphone port sprites. He has a matching cape and carries a katana.
Cyan has a distinguishable pseudo-Early Modern English manner of speech, using archaic expressions such as "thou", "dost", "thy", and referring to males with the title "Sir". In the original Japanese he speaks in a characteristic "samurai" manner, using the pronoun sessha and ending sentences with de gozaru. This prompts Gau to nickname Sabin "Gozaru" in the Japanese release, or "Mr. Thou" in the English games. De gozaru is a rough or uncultured way of saying de gozaimasu and is used by a samurai or ronin or yakuza in film or television to denote masculinity and ruthlessness. Cyan writes the same way he speaks, and when reading a letter from him in the World of Ruin, the party instantly recognizes his style.
Being a survivor of Doma's poisoning, Cyan is plagued with survivor's guilt, blaming himself for Doma's fall and believing to have lost his honor. He is adverse to displays of affection. Due to Doma's simple lifestyle, Cyan is technophobic and struggles operating machines, but overcomes his fear. When he rejoins the party in the World of Ruin, the party can find several basic books about machines suggesting he has been trying to learn about them. If the player speaks to Cyan while onboard the ''Falcon'', he will be staring at the engine, commenting it is "an interesting apparatus".