Iku, better known as Number 19, is one of the secondary antagonists of the webcomic/manga Calendar of Vengeance.
19 is a member of the pop star group known as Calendrier, made up of thirty one girls to match thirty one days of a month. 19 told numbers 30 and 27 to bully Number 31, who is the most recent member. However, one day, 31 snapped, and started to kill her bullies. After killing 30 and 27, the latter of whom revealed that 19 was the one who told them to bully her, 31 set her sights on her.
After confronting 19, 31 questions 19 why she was the source of her bullying, to which she responded by calling 31 a "useless gutter rat", claiming 31 didn't deserve to be in this business.
19 then staged an encounter with a employer of hers named Mr. K, and her plan was to have 31 take drugs that would cause her overdose and be killed. However, 31 figured out 19's plan, and managed to turn the tables by purchasing her own aphrodisiacs and taking them instead of 19's pills. However, she also got additional aphrodisiacs, which were ten times stronger. When mixed with the original aphrodisiac, it would cause a chain reaction that would kill the person using it. She killed Mr. K with this method, and made 19 take the ten times strength pill upon entering by switching her pills with the new one on the nightstand, and then kissing her and forcing the other pill down her throat to make sure 19 consumed both of the different aphrodisiacs.
Upon revealing to 19 that she was going to die, the aphrodisiacs kicked in, causing 19's body to light up in painful pleasure, and she couldn't think straight. 19 begged for help as 31 continued to fuck 19's body, but 31 just continued to mock 19. As 19's body could not handle the pleasure she was feeling from the aphrodisiac overdose chain reaction, she climaxed to death with an ahegao on her face.
