Megumi Aso (麻生 恵, Asō Megumi?) is a famous model and the daughter of Yuri living in the year 2008, born on December 29, 1987. As a Fangire Hunter and as Yuri's daughter, Megumi makes it her duty to hunt down the Fangire as well as finish her mother's unfinished affairs, such as the Rook. She meets Wataru and develops a liking towards him after helping him with his allergy issue, unaware that he is actually Kiva himself. She is also not afraid to tell him off whenever he acts strange. While Keisuke Nago has expressed his interest in her, Megumi cannot stand him and was reluctant to notify him of Kiva's reappearance. Her weapon is a rather small pistol that shoots slugs at high velocities, with an attachment which shoots out a chain that resembles her mother's Fangire Slayer. It seems that she shares her mother's cynophobia.
Over time, she starts to see Kiva in a different light as he continues to fight the Fangire, rescuing her on more than one occasion in the process. When her younger brother named Mitsuhide Aso (麻生 光秀, Asō Mitsuhide?), the Fangire Hunters' benefactor, comes to reclaim his sister, Megumi refuses to leave and convinces her brother to let her remain after destroying the Rook using the Ixa System. When Shima orders the elimination of Kiva, together with Nago she tries to assassinate Kiva but cannot do it. After Kiva's Fangire blood reacts he jumps on the bridge and grabs her and was going to kill her when Nago intervenes leading Kiva to regress back to Wataru to her shock. Back at his house she, Shizuka and Nago try to cheer Wataru up but to no luck. Megumi, along with Ryo Itoya, are the only two of the 2008 Ixa users not to use the Rising Ixa form.
Megumi would later play an important role in Nago's life after his eyesight was revealed to be failing, encouraging him to continue as Ixa when he considered quitting the Wonderful Blue Sky Organization. After the final battle was over, she would marry Nago a few days later. After marrying Nago she tried to fight the future threat with her husband and the other Riders only to be stopped by the guests for fear of ruining her dress.
In the S.I.C Hero Saga side story King of Vampire, at the end of the wedding Kiva-la shows up instead of Masao Kurenai to warn everyone about the threat of the Lion Fangire's Sabbat. Kiva-la chooses Megumi to become Kamen Rider Kiva-la.
Megumi Aso is portrayed by Nana Yanagisawa (柳沢 なな, Yanagisawa Nana?).