Fuyubachi

Fuyubachi is an elderly man who connects with Zebra and Kamome online, and they arrange to meet in person to commit suicide. They all carry Maromi backpacks to help identify one another in the crowd upon meeting. He waits with Zebra, wondering where Kamome is, and is shocked to discover that Kamome is a young girl.
The episode hints at why Fuyubachi wants to die. On the train, he murmurs "Sayo" in his sleep; he is also carrying a bag of Chitose Candy, which is given to children at ages three or seven. This suggests that something may have happened to a child named Sayo in his life. The child could have been his grandchild and might have died recently, before Fuyubachi could give him or her the candy, or it could have been his own child, who abandoned him.