Casino Dealer Delmo is a member of Black Delmo.
She is first seen working the Roulette at the Casino in the Hotel the K-2 Corporation members were visiting on their vacation during the events of The Golden Delmo Operation. Initially she is seen letting Gozo Aida win at Roulette, yet later she seems to send him on a harsh losing streak.
Later during the events of Delmo Operation: White Silver she is seen as part of the crew who is assigned to capture Gozo Aida. While flirting with the man and getting him to consume multiple drinks, she is at one point alarmed by the fact that he seems to vaguely remember her. However the danged is averted when another of the Delmos present distracts him by putting him to sing karaoke.
Finally, when the girls think they have successfully inebriated Gozo enough for him to be unable to defend himself, she and a group of fellow Black Delmo rush him in an attempt to take him out. Unluckily for them, their effort is futile, as even drunk he remains as much of a hard opponent.
During the fight, Casino Dealer Delmo charges Gozo from behind as he is making quick work of another girl, and tries to land a hard blow aimed at his face. However, Gozo, even though drunk, is still too fast for her, and manages to easily evade the hit, as the girl loses her balance from the failed attack. This leaves the poor Delmo leaned forward standing in one foot, defenseless in a fairly unstable position, as Gozo quickly takes advantage of the situation and rotates 180º to finish her off with a devastating back kick to her face. The sheer force of the impact sends her flying several feet, flipping mid air and landing face down with her legs wide spread. However, she is later seen knocked out in a different position when Nina Etsuko attempts to contact her unit for an update.
We can only assume Gozo might have moved the knocked out girls' bodies after the fight in search of useful information or elements.