The culprit is Kinji Ogawara. Naoto Kishitani indirectly cause Ryoichiro's death. After the case, Rum detects Rumi and plans to have Chianti and Korn eliminate her.
In the flashback, Haneda headed to Amanda's room, and the true name of Asaka was Rachel Asaka.Haneda also pointed out that the disease of her eye is Amaurosis Fugax.
Amanda and Rum met when Rum was still a child.Rum said he got his codename from his deaceased father.Amanda swallowed APTX in order to protect Asaka.Haneda hid Asaka and told Rum he saw a piece of news including Rum gave a speech for Renya Karasuma 30 years ago.Rum decided to kill him.