Ryōko Komatsu is a renowned detective who publicly champions the new detective duo Feathers on her television talk show, boosting their visibility. This high-profile support makes her a target for the antagonist group Coloured Phantom.

Komatsu is unmasked as Yellow Black Hole, a Coloured Phantom member. Operating under this alias, she steals her own detective license to set a trap, using it as bait to lure Feathers into a confrontation. This phantom thief identity marks a deliberate break from her public image as a law-abiding detective.

Her background includes prior detective service, fostering admiration for the profession. However, disillusionment stemming from an unsolvable mystery triggered an ideological reversal, motivating her to join Coloured Phantom. There, she collaborates with Blue Hunter, another member posing as a media personality.

Komatsu attempts to recruit Feathers into Coloured Phantom, asserting their skills are better suited for phantom thievery than detective work. This offer reflects her belief that detectives and phantom thieves embody irreconcilable opposites of justice and crime, a core tenet of Coloured Phantom's war against compromised phantom thieves. Her actions directly challenge Feathers' ideals and confront them with ethical ambiguities.

Her tactics involve psychological manipulation, such as citing her unresolved case to erode Feathers' trust in the detective profession. After her identity is exposed and the recruitment fails, she escapes with Blue Hunter, leaving unresolved questions about her past and the nature of her disillusionment.