Yakuza 4 Edit
Disbanded the family immediately after the Yoshiharu Ueno shooting in 1985 and vanished. He was planning on using the assassination to quickly defuse the conflict as a mediator in the conflict but Shibata and Katsuragi found out his plot and used this opportunity to annihilate the clan as well as allow Katsuragi certain hopes of succeeding as their Chairman. He was found by Majima, half-dead, and was taken to Purgatory, but wouldn't react to anything. After Saejima escapes from prison he is reunited with Sasai, who says Saejima's name, his first words in 25 years. Before his descent into dementia, Sasai was adherent to using the threat of force over wealth to establish a clan's authority. Such values are passed on to Saejima in his substories.
Being a homeless person, Sasai has an unkempt appearance. He appears to be catatonic and likely suffered from dementia.