Biyomon (World Data Squad)

Biyomon is Kosaburo Katsura's partner and one of the six Rookies which make up the party. This one male, he is capable of digivolving to a whole host of Digimon, though his main evolution is Birdramon, displayed in one battle against the player prior to joining.

Digimon Data Squad
When the DATS team saves a young boy who had become a part of 's data, Biyomon swoops in and snatches the Code Key of Sloth from the team before they had a chance to analyze what they had found. Kosaburo appears and taunts the team a bit, thanking them for doing his job for him before escaping with the Code Key.

Kosaburo appears again when the DATS team save a young girl who gotten trapped in the Digital World and had become a part of 's data. Biyomon again swoops in and snatches the Code Key of Greed from the team. Yoshino demands to know what he's up to and he replies by teasing her about her scary face and how it sabotages her relationships, indicating that he and Yoshino know eachother pretty well. Inevitably, he escapes again.

When the DATS team rescue the next child from, Thomas and Gaomon prevent Biyomon's predictable attempt to capture the Code Key of Lust. Kosaburo, determined not to fail his client's request, produces a Digivice iC and evolves Biyomon to Birdramon. They attempt to take on the DATS team but with 's help, Biyomon is defeated and they are forced to flee.

Unable to collect the Code Key, Kosaburo contacts his client and informs him of the situation, noting that the client had gone to great trouble to keep his identity secret. Kosaburo and Biyomon are attacked by one of the Demon Lord digimon,.

From that point on, Kosaburo occasionally lends a private eye's perspective to tracking Kagura and solving the mysteries of his plans, as well as helping Biyomon to fight in the numerous battles to stop the resurrection of the Great Demon Lord Digimon,.

After defeating Kagura, it is presumed that Kosaburo and Biyomon return to their private investigator work, provided that they don't interfere with DATS missions anymore.

Birdramon
Birdramon is Biyomon's Champion level form.

Birdramon first appears when Biyomon fails to steal the Code Key of Lust from the DATS members. Kosaburo then reveals he has a Data Link Digivice, and then charges his DigiSoul allowing Biyomon to digivolve into Birdramon. He is then defeated by the DATS members and reverts to Biyomon.