Taikoubou
太公望
Taikoubou is around 72-year-old Senin (Immortal). He was sent to the human world to execute the Houshin Plan, which was to trap the souls of the Youkai's (demons) who are evil. He's very lazy yet smart at the same time. He also doesn't like the loss of life and tries to prevent it at all costs.
Manga