A manga written by Mizukami Satoshi, who is best know for writing The Lucifer and Biscuit Hammer."Stop your evil deeds and take the right path!"That is the creed of Tama and her younger step brother, Jinka. The two demon siblings travel the country to stop the deeds of all evil doers, along with a cowardly swordsman they picked up along the way, Hyoudou Shinsuke. Their travels lie with many twists and turns, as well as wacky characters they'll meet along the way.
Time Skip - Of roughly four months. And then 8 years in chapter 53.
Took a Level in Badass - Shinsuke goes from being a coward who has lackluster sword skills to Badass Abnormal. All of the characters undergo this, Shinsuke and Jinka's badass levels are perhaps the most obvious.
Jinka's an extreme case of this. He goes from four tails at the start of the series to a thousand! Deconstucted as this rapid rise in Power Levels makes him go completely insane, starting part two, where the aim is to find him and cure him of his madness.
"Well Done, Son" Guy - Jinun has never shown overt affection towards Senya, and had his son address him as Master as opposed to father.