When Rikka was younger she used to go on deep-sea diving trips with her family during the summer, during which she was able to bond with both her parents greatly, building a great relationship with her father. Eventually after a few years, Rikka’s mother passed away due to a terminal illness, and her father was forced to get a higher-paying job, and so he couldn’t spend as much time with Rikka. Their relationship became torn through small meaningless arguments and spats, causing Rikka to miss the older pastimes of scuba-diving, so she began to do it herself or with her friends when she got older. Eventually, she became well known for her dives, reaching magnificent depths that most people couldn’t even imagine. After a while, she was recognized by Japan’s government as the Rising Ultimate Scuba-Diver. Although after she accepted the invitation to the Banquet, she may have gone a little deeper than she thought she would.

This is a supporting role.
Rikka is lead by her emotions greatly, and wears her heart on her sleeve. In the death game she is very rude and harsh because of the stress she is enduring.