Dr. Aris (Kor. 닥터 아리스) is a high-ranking Union scientist and modified human under the command of the 12th Elder. She is also the creator of the DA-5 experiment(Doctor Aris, hence DA), and served as their direct superior.
Dr. Aris has golden eyes and long red hair that extends all the way to her waist. She is slender and considers herself very attractive, which is shown by her being confident enough to collect men from various countries as souvenirs and expecting all of them to be interested in her, She was dressed in goth-style clothing in her earlier appearances, which comprised of a short black top with white outlines and elbow-length sleeves that left her mid-riff bare, and a short black-and-white coloured frilled skirt that stopped half-way down her thighs. She wore two large hoop earrings, a black choker necklace and black gloves. She also wore a pair of black and white leg warmers that extended up to just below the knees, and a pair of wedge slippers with flowers on each. By the time Frankenstein was brought to her, the sleeves and gloves had been removed, replacing them with two black bracelets on her right hand.
She has a twisted personality and is impulsive to the extreme. She initially presents herself with an innocent, childlike demeanour, but is very cruel when it comes to experimenting on humans. She also doesn't care about her experiments and made them use their life energy while fighting which could kill them. For example, she tells her assistant, Yuri, to collect "souvenirs". These "souvenirs" are humans that Dr. Aris would experiment on. Dr. Aris is also very demanding and psychotic; after the capture of Frankenstein, Frankenstein attempts to leave but is threatened by Dr. Aris who demands that he withdraw his leg from the door frame threatening to cut his leg. She can get extremely angry when she is disobeyed, like when Frankenstein leaves against her wishes, she orders her human-machines to eradicate him.
She doesn't have much respect for her higher officers as she kept insulting Dr. Crombel and even the 12th Elder.
Dr. Aris is the scientist who created DA-5, frequently referring to them as her children. Dr. Aris fabricated the identity of 'Teira', the younger sister of Takeo, for her own enjoyment simply because she was bored with just experimenting all day and she enjoyed the reaction of Takeo.
Dr. Aris arrives in Korea after the DA-5 gets annihilated to investigate the incident. Yuri and two other modified bodyguards come with her. Investigating the battle site, she concludes that all her 'children' are dead and somehow Crombel is related to all of it. With nothing else to do, she order Yuri to collect a 'souvenir' for her. Yuri stumbles upon Frankenstein and finds him suited to Aris' taste. So, he kidnaps Frankenstein (who actually comes along intentionally to find out more about union) and brings him to Aris. She finds him quite a handsome souvenir to conduct experiment on.
However, when Raizel texts Frankenstein to come home his acting is revealed. Ignoring Aris' warnings, Frankenstein attempts to leave but is stopped by her bodyguards. Fights break out and Aris is surprised to see Frankenstein defeat her subjects easily. She steps in herself and uses nano suit to fight Frankenstein. Even so, Frankenstein has the upperhand.
Takeo intervenes the fight to protect Aris whom he knows as his sister. It is then revealed to be a trap by which Aris holds Takeo hostage. While attempting to drain Takeo to escape from Frankenstein (as she is the other person besides Kranz who can absorb the energies of DA-5), she takes the strawberry-flavoured pill from Takeo's pocket which is formulated by Frankenstein. However, she collapses after taking the strawberry flavoured pill which supposedly should have increased her power 200% for a brief period while rapidly consuming life force. Frankenstein states that while D was specifically made for her, the pills he gave them were tailor made for Tao and Takeo without considering Dr. Aris. That and since he doesn't have any previous data on them when they had used D he can't say for sure what would've happened if they took the strawberry pill also.
Yuri takes the unconscious Dr. Aris to Dr. Crombel where she still remains. But whether she'll recover or not is unknown. Physically she's believed to eventually recover from the damage of so much life force lost, but that will take quite a while. Mentally is harder to say other than that every time she wakes up she starts kicking while expressing extreme fear before getting sedated. Currently Dr. Crombel is having her taken care of in the hope of her brain recovering (whether her body recovers doesn't matter to him) as Union wouldn't give up her knowledge easily. He's keeping her condition and the existence of Raizel's group a secret while "leaking" information to make Union think she is fine.
Aris recovers from her condition thanks to Dr. Crombel and she is now under the direct control of her former rival. She leaves the hideout without permission and goes to South Korea in search of test subjects.
Having escaped from the lab, in search of test subjects, Aris witnesses the fight between Shinwoo and a gang of teenagers, she notices his potential, and takes an unhealthy liking to him.
Yuri and Mark appear to take her back but she is adamant on taking Shinwoo with her as an experimental specimen. Yuri tries to stop her but gives in to her demand in order to satisfy her. Their plan is ruined by the sudden arrival of M-21. Aris is enraged at the interference of the 'failed and disposable experiment' and attacks him in her nano-suit. They believe that the attack was too strong and assume that M-21 is dead. However, the smoke clears and they are shocked to see M-21 in his werewolf form. Aris swings her energy whip at him but M-21 catches it to bring her to him, punching her in the guts and knocking her unconscious.
After gaining consciousness, Aris is both angry and shocked by M-21's werewolf powers. She wonders aloud how a failed experiment could have gained such power which even the Union failed to achieve. She is jealous of M-21 and tells him to be thankful for such wonderful power. She is about to be killed by M-21 when Muzaka arrives. The sudden appearance of Muzaka pacifies the situation. Before departing, Aris begs Muzaka to let her take the experimental specimen (Shinwoo) along with her. However, no sooner than she makes the request, she finds herself at the mercy of Seira's Death Scythe. Muzaka brushes off Aris' request and they return to their hideout.
Dr. Aris possesses considerable power for a modified human, being stronger than any of the DA-5 members to the point that even Kranz was scared of her. However, she was only able to briefly hold her own against Frankenstein, blocking some of his energy attacks but was gradually overwhelmed as he exerted more power.
Her body is covered in a nano-suit, which greatly augments her power. The suit is pink, with some blue outlines. In this form, she is able to manifest two large energy whips from her palms. Her overall power is enhanced to an impressive degree, to such an extent that she was able to parry some of Frankenstein's attacks even after he released his seal, though eventually she wasn't able to keep up with him. She mainly fights in this form using the whips, both for offence and defence, lashing out with enough power to cause serious damage to her surroundings and rapidly spinning, simulating the appearance of a miniature cyclone to defend against Frankenstein's energy attacks.
She can absorb the life force of modified humans. The DA-5 team was created for the sole purpose of serving as her back-up power source, so she could eventually absorb all their abilities in the future. It enhances her powers tremendously, similar to Kranz.
Like the DA-5 members, she could also enhance her abilities through the use of D. Realising Takeo has been carrying 'D' with him, she takes hold of those and consumes the 'D' without knowing they were modified by Frankenstein. It rapidly increases her power to 200% but then, in a few moments, all of her life energy drains due to overexertion,and her mind is destroyed.