If you liked the Urusei Yatsura anime, the Anime-Planet community thinks you'd like:
Protagonists Moroboshi Ataru and Igano Kabamaru share a love of food, sleeping in class, girls, and making the most of their school days. While Urusei is vastly superior imo, fans of the comedy in one may like the other of these early 80's anime.
Keitaro Urashima is somewhat of a failure. In order to fulfill a promise he made to a girl fifteen years ago, he has tried time and again to get into Tokyo U but has never managed to pass the exam. However, fate smiles upon him and he ends up working for his aunt, managing an all-girls dorm! Living with the feral Kaolla, the timid Shinobu, the sake-loving Mitsune, the blade mistress Motoko and the punch-happy Naru, can Keitaro keep his focus and keep his promise? And will he ever end up meeting that girl from his past?
Both are similar romantic comedies. Lum and Neru are both short tempered and have a tendancy to be violent. Ataru and Keitaro are both bumbling fools, though Ataru is more open with his fantasies. Both are quality series and well worth the watch. Both series have a host of great supporting charecters with unique personalities.
Maiku Kamishiro has always had a photo of himself as a child in front of an old house with a young girl. One day after spotting the building in a news report, the high school boy moves to the countryside to live in the house from the picture. While living alone, making ends meet by working as a freelance programmer, Maiku gets the shock of his life when not one, but two girls turn up on his doorstep claiming to be his twin sister! With the lively Miina and timid Karen both possessing the same photograph, the pair begins living with the confused Maiku as they try to figure out which one of them is actually his sister.
While visiting his hometown, junior high school student Michishio Nagasumi's life was changed forever when he nearly drowned. Though he was saved by a mermaid named San, there’s a catch -- her family is part of a merfolk mafia, and they abide by a strict rule: If a mermaid is discovered by a man, either he or the mermaid must die. That is, unless the man marries into the family! Faced with such a decision, Nagasumi can only oblige their customs and become a "happy" newlywed. Now, with a new school year around the corner, Nagasumi must find a way to deal with his new bride, keep her true nature a secret, and most importantly, escape inevitable death at the hands of San's over-protective father’s gang!
Both animes are similar in plot, scenario and even the characters (though, Urusei Yatsura came 20 years before Seto No Hanayome). Both shows are about a boy (Nagasumi/Ataru) who ends up getting to a moe'-like non-human girl (an alien and a mermaid) who looks like an ordinary human girl,much to the annoyance of his disappointed parents, the mother who regrets getting married and the father who always worried about his mortgage. After the girl's (San/Lum) extreamly strong, big father forces the marriage against the boy's wishes, the girl ends up living with the boy. Then a host of similar (because they're pretty much the same in both animes) characters appear such as the extreamly sweet, pink-haired scznophrenic bitch (Luna/ Ran) who's the childhood friend of the girl and a extreamly wealthy, powerful heir to a Japanese conglomanate company who always wears a white suit, speaks about honour and uses a samurai sword. Cue similar plot devices such as fan clubs for the girl (San/Lum) and the pink-haired childhood friend (Luna/ Ran) who are constantly at war, old fiances and an extreamly sexy school nurse (Ran's mother/ Sakura)who's connected to the boy in some way and once you watch 'Seto No Hanayome' and 'Urusei Yatsura', you real realise how similar the two shows are.