O.D was born and raised on a distant planet between a native and an Earth human. O.D gained their NOTE through some unknown event. One day, Berg Katse appeared and had the people of O.D's planet turn on each other. O.D found Katse and fought him in their Gatchaman form and while they managed to damage Katse, they ended up destroying his home planet. Katse had thought that O.D was dead when they really just went to Earth.
They are pale-skinned with purple hair. They always wear a purple top with tight, black jeans, and black high heels, and have a black top hat (although they do not often wear it).They have red eyes with yellow lipstick matching their nail varnish.
Their GALAX avatar also wears cat ears, a black skirt, and thigh-high high-heeled boots, similar to concept art for the character.
They have a happy personality, often livening up the atmosphere if they deem it too gloomy, although they also airily make reference to rather morbid ideas (mentioning to Utsutsu "you'll be fine even if I was gone", contemplating what their final words should be). They are very caring to all members of the G-team.
The mood-maker of the Tachikawa "CAGE" with the catchphrase of "You're overdoing it-!!" They call themselves "a sad Gatchaman that can't transform," and because of this they do not go on normal missions. With their guardian-like existence to the team, people who might not open up their hearts to others would open it up to them. They own a cat named Altair (Al for short). In episode 8, it is revealed that they are half human.
Not much is known about their past except that Berg Katse destroyed their planet and that they were once defeated in a fight with Berg.
Early in the series, OD stated that they were a "sad Gatchaman who can't transform". This is in reference to the fact that their immense powers would be highly destructive, annihilating the Earth and ultimately ending everything if they used it.
They possess a green colored NOTE. During Episode 12 they finally unveil their G-suit and proclaim that they will make Berg Katse disappear with "these arrows of annihilation" which are long beams of light that come out of the wings. They proved to be extremely powerful as they destroyed more than half of Berg's body with just two attacks. Berg Katse also reveals that during their fight, OD was responsible for the destruction of their home planet when he fought against them in the past.