Happosai (Ranma 1/2)

Happosai (八宝斎) is a major antagonist in the anime and manga Ranma ½. He is the legandary perverted master of the two main characters' respective fathers Soun Tendo and Genma Saotome who returned to ruin their lives.

Why He's Loathsome

 * 1) The only defining trait of Happosai is his perversion. Not only that, he is extremely unlikable and his thing with outright stealing women’s undergarments, fondling their breasts, and flipping skirts without their consent is very intolerable and creepy. There are so many things wrong with him you can’t even list them all.
 * 2) He is more of a plot device than a character, adding to how he is overused in the anime to the point where it gets old, and serves as a filler in general.
 * 3) He shows absolute NO remorse for what he does.
 * 4) Even the characters in the series can’t stand him.
 * 5) He is also apparently a pedophile as he is frequently harassing Akane, Ranma (in his female form), and many other girls when he gets the chance. At his worst, he once had Akane knocked unconscious and kidnapped her so he can sleep with her. On top of it, Akane is 16 years old, which is again creepy and disturbing.
 * 6) He is selfish and lies to advance in his game. To add insult to injury, he is devoid of sympathy and is oblivious to the feelings of the people he hurts.
 * 7) He is a horrible and cruel master to Soun and Genma. During their training, he used them like tools to participate in his BS. He also used Kuno as a decoy so he could steal undies and bras for his own personal enjoyment.
 * 8) He is so immature and plays victim whenever he gets called out.

Redeeming qualities

 * 1) Despite the above mentioned, he does have his funny moments.
 * 2) His comeuppances for his actions are satisfying.
 * 3) His touching backstory with Cologne, although he stole her mirror and other things from several other women, which caused Cologne to hate him.
 * 4) He is an excellent martial artist.
 * 5) He is at least self-aware. In one episode where he was trying to get his young self to avert his lecherous ways.