Ken Otonashi

Ken is the first member of Kurokiri Genk(after Mukuro).He died 3 years before the story of reborn season started because protecting Delya from a mafia's deadly attack.

Mukuro&Delya's Memories(This Including His History)
He is being a mafia's evil experiment with Mukuro when child.After Mukuro kill the one who do the experiment,Mukuro wants him to be his comrad,and he is agree.When Delya first come to Kurokiri Palace,he thinks she is an intruder but Mukuro explains that she is his new friend.2 months later artemis come to the genk and join Mukuro.He,Mukuro and Artemis talk about Delya's mother is take another child become her student after Delya run away from the hospital.Delya that bring tea cries and release her dark energy until Mukuro stop her.1 years later,he and the other of past member kurokiri genk fight a big Mafia Group.When almost win,Delya almost die by the opponent's Sword,but he protects her and resulted him in almost die condition.Before die,he told Delya not to cry,and please protect Mukuro-sama,and he say thank you to Mukuro.

Relationship
-Mukuro Rokudo

His friend and master.

-Delya Kazuma

His friend,he often slap her and call her baka,but when she is in danger,he always help her and blushes.He even die because protect delya.

-Artemis

His comrad.They are best friends and totally loyal to Mukuro.Different to artemis,he serve Mukuro not because he want something from him but because Mukuro already saved him.