Kamira and Kurusu Kotara

Kamira Kotara (湖多艮守羅 Kotara Kamira) and Kurusu Kotara (湖多艮繰守 Kotara Kurusu) are twin sisters who only appear in Twin Succubus, UMEMARO 3D's ninth release. They first appear as supporting characters, but are later revealed to be the final antagonists of the game.

Appearance
Kamira and Kurusu, being twins, have almost identical body builds. Kamira's skin is tanned, while Kurusu's is pale. Kamira's face is also slightly sharper and more angular, while Kurusu's is rounder and softer. Kamira has long pigtails and bangs that cover her forehead, while Kurusu has shorter pigtails and a split part in her hair. They both wear black schoolgirl uniforms with gold accents and purple ribbons. In their succubus forms, they gain leather accents across most of their bodies while leaving their breasts exposed, along with large wings, slitted pupils, fangs, tails, and accented eye makeup (green for Kamira, purple for Kurusu).

Traits
Kamira and Kurusu, as twins sometimes do in media, act similar to one another - playful, but also aggressive. Being succubi, the two of them feed off of sexual activity, and are more than willing to kill their prey when they've had their fill. All three of their sexual partners in Twin Succubus are killed in this manner. During sex, they will act submissive and defer to their male partners until it is time to finish up, during which they suck the life force out of their partners and kill them.

Abilities
As mentioned above, Kamira and Kurusu are succubi. They can make themselves appear human at will, though their succubi traits will manifest when they are feeding. They feed on sexual activity, and as their partner climaxes, he will die, as the succubi drain his life force during the climax. They are apparently also capable of doing this without killing their prey, if necessary.

in Twin Succubus
Kamira and Kurusu's only appearances are in Twin Succubus, where they are the titular succubi. They are brought in by Chokugen and Mimi Minami in order to serve as sex slaves for Chairman Ohara and Hosokawa, as part of the men's nightly raping of girls from the University of Yomei. Things initially go as planned for them as Kamira and Kurusu pretend to be hypnotized, with one girl being double-teamed by Ohara and Hosokawa, and the other having sex with Shinnosuke Nakata, Ohara's assistant. The player chooses one for Nakata to have sex with, and the other is sent over to Ohara and Hosokawa. At first, the player's choice stays with Nakata, but soon the other girl comes over and demands to have sex with him, having finished off the old men. This is shown in a separate sequence, where the two double-penetrate her until their souls are drained during their mutual climaxes. As both girls drain Nakata, he begins to lose consciousness, staying awake just long enough to see them turn into their succubi forms, and seeing Ohara and Hosokawa dead on the ground. When Nakata wakes up again, Kamira and Kurusu have abandoned their human disguises, and proceed to have sex with him again, draining his essence completely and presumably killing him. A post-credits scene implies that this was the plan all along from Chokugen and Mimi.

Trivia

 * Despite the release of Twin Succubus before OMEGA, Kamira and Kurusu do not appear at any point in the duology. This is because Twin Succubus was developed during a break from OMEGA's development, and there was likely no way to cleanly integrate the twins into the game at that point.
 * This makes Kamira and Kurusu the oldest female characters to not appear in another game after their debut. This trait would later be shared with several characters after the OMEGA duology.
 * DLsite's official translation provides the surname "Gotara" instead of "Kotara" for the twins, despite promotional imagery (and direct translating of the twins' names) indicating that "Kotara" is the correct spelling. It is unknown if this was deliberate or a spelling error.