Hololive Dark : Goodbye Kaichou

Tokina Sora has mysteriously disappeared and this caused the SCP Foundation led by Mr Nobody to visit the Hololive office. Yagoo and A-Chan are warned by the SCP Foundation official that Hololive will be closed forever if Tokina Sora is not found as soon as possible. This is because Tokina Sora is very dangerous if she is not monitored properly and it is certain that Tokina Sora will lose her life if the SCP Foundation first finds out. This created fear in all Hololive members because they did not want to be in the SCP Foundation prison anymore.

Kiryu Coco, the yakuza dragon decided to look for Tokina Sora alone without Yagoo's knowledge. However, she begins to reveal various secrets that have long been hidden by Yagoo about the SCP Foundation and the life histories of other Hololive members.

'Daifuku, take Lamy away from here. Say that mother will always love her . '
Said Queen Yukihana, the last ruler of the Land Of Silver

'Tokina Sora has a very dangerous mysterious power. If my team found her first, I would immediately order my men to kill him. I am doing this for the good of mankind. '
Said Mr Nobody, leader of the SCP Foundation

'I used to be a hot -blooded young man who liked to cause trouble. However, one incident happened to me and brought me to full consciousness. '
Yagoo said to A-Chan

Who is a man named Sabang?
What does this human have to do with the disappearance of Tokina Sora?
What is the relationship between Project MKUltra and Sabang?
Why does Yukihana Lamy often shiver in fear of hearing Sabang's name?
Why does Usada Pekora seem to know Sabang?
And more importantly, why is this story titled 'Goodbye, Kaichou'?