Tonia has silver-colored hair, which she fashions in a long braid, reaching hip level, adorned with a light green ribbon. She also has green lines along her Golden Delmo Uniform to differentiate her. She uses steel claws as her weapons of choice.
Tonia and Sania are first seen planning an assault on the K-2 Corporation Building. She confronts Aika Sumeragi in the dark and manages to entertain her long enough for Sania's bombs to blow up the building, Tonia then jumps out the window and lands in a car driven by Sania to make her escape. She later appears alongside the other Golden Delmo in the final confrontation. Having believed that Aika is deceased, Tonia and the Golden Delmo, prepare to finish off Aika's friends. Suddenly Aika appears in her Shivie Form, briefly scattering Tonia and the rest of the Golden Delmo. Regrouping, they charge at Aika for a final battle. Tonia lunges at Aika but is kicked in the head and her unconscious body sent flying while flipping in the air. Before the end of the fight we get a last view of her defeated body: she lies sprawled on the ground, face up with her legs spread and half her skirt hiked up, partially exposing her panties. She has her mouth wide open in an expression of anguish.
Together with Rie and Bianca, Tonia is one of the few Delmos who manage to fight by herself on moderately equal terms with Aika.
In the opening battle, she is aided by the element of surprise, being able to strike first against the unsuspecting salvager. This allows her to land a few blows before Aika is able to stand her ground. The initial advantage doesn't last much though, as Aika gets hold of a camera which she uses to momentarily blind the attacking Delmo. By the time Tonia recovers, Aika is already in mid air, landing a demolishing kick with his high heel on the girl's face. The odds now matched, they both then fall to the ground, where they struggle for some time, before Tonia manages to break the stalemate with a headbutt. The move startles Aika, who loses her footing and ends unceremoniously back on the floor. Convinced of having the upper hand, Tonia then goes for a fancy final airborne attack with her claws. Still affected by the previous blow, Aika seems to barely be able to defend herself by throwing a chair at the oncoming Delmo, but the obstacle is quickly reduced to shreds by Tonia. However, once the item is dealt with, it becomes clear it was a just a distraction, as the falling debris reveals an ever ready Aika preparing another fatal move. Caught by surprise, the Golden Delmo is only able to gasp in shock as the salvager delivers yet another hard kick to her face, which stops her in mid air as it causes her to spreads her legs.
Despite all this beating, Tonia shows her resiliency by failing to fall unconscious. We do not know what happens after this last move, but it is clear both girls still struggle for some time, equally unable to gain the upper hand over one another. The fight is eventually cut short when Sania's bombs go off, and Tonia hastily makes her escape by jumping out the window, technically undefeated. No other Delmo in the original Agent Aika holds such an honorable distinction.
By the final battle, Tonia's luck seems to have totally ran out. From being able to spar with Aika for minutes in their first confrontation, this time the girl is barely able to put up a fight against the salvager in her Shivie form. Once more the Delmo tries to resort to the element of surprise by charging Aika from behind as the heroine is busy making quick work of Rie, but this time the strategy is a total failure. Not only does she miss the attack with her claws, but in the move leaves herself completely open for a retaliation. Aika does not lose the opportunity and, before the Delmo has even time to brace herself, responds with a brutal flying kick to her forehead. This time this is all that it takes, and Tonia is thus unceremoniously left out of commission, her knocked out body falling to the ground.
- Every time Tonia is hit by Aika, the move is a kick to the face. This happens 3 times, but only manages to knock her out once, during the final confrontation.
- Tonia's Page on Villainess Wiki (in Japanese)