Fifteen-year-old Tsukune Aono is average in every way; he has no hobbies, less-than-stellar grades and he's even flunked his high school entrance exam. His parents have managed to enroll him in a school, but it's no ordinary school! Tsukune will be attending the Youkai Academy, a place where monsters learn how to co-exist with humans! As the werewolves, vampires, witches and other monsters are required to retain their human forms, Tsukune - the lone human - is able to avoid their bloodthirsty gazes. However, he quickly attracts the attention of a number of devilish beauties including the vampire Moka, a busty succubus and even a young witch! It seems Tsukune's average life isn't so average anymore!
Ceres: Celestial Legend and Rosario to Vampire, although seemingly unrelated the personalities between Ceres and Aya and Mako’s vampire form and human form have similarities in the characteristics they portray. The transformation has a more mature attitude and seems to be more capable all around while untransformed there is an innocent girl in place that relies on others for help.
You know the drill: monster girl harem. Both Rosario to Vampire and Deadline Summonnr are about that.
In the near future, some girls are born mutated. Known as Diclonius, this new species is believed to have been chosen by God to wipe out mankind. Unlike regular humans, Diclonius have two horns on their head and ‘vectors' - invisible ‘hands.' Contained within a research facility unknown to the world, the Diclonius are experimented upon mercilessly; many die or develop a hate for mankind. One such creature, Lucy, is said to be the first of the Diclonius. She escapes from the facility, but while fleeing she takes a bullet to the head and is seemingly killed. However, it seems Lucy isn't quite dead yet; she's instead developed an alternate personality called Nyuu. She's washed up on a shore where two people, Kouta and Yuka, find her and bring her home, unaware that such a monster still lurks within Nyuu.
Rosario to Vampire and Elfen Lied, although seemingly unrelated the personalities between Lucy and Nyuu and Mako’s vampire form and human form have similarities in the characteristics that each portray. The transformation has a more mature attitude and seems to be more capable all around while untransformed there is an innocent girl in place that relies on others for help.
Takaya is the strongest and most handsome guy in school, but also the most misunderstood. His life is irretrievably changed one day when he finds a mysterious pendant and opens it - to his surprise, out pops a beautiful girl with F-cup breasts and wings on her back! Her name is Lilim, she's a succubus, and she also happens to feed off the life energy of humans. Unable to seal her away again, Takaya persuades Lilim not to feed on others, but to stay with him and only take his life energy. However, is Takaya really prepared for the consequences of having a beautiful, live-in succubus interfering with his life?
Both animes are about an relation between a demon girl and a human boy, both animes have their funny scenes and the love triangle. I think if you like one you would like the other
Urashima Keitarou is a loser. He's failed the Tokyo University entrance exams two years in a row, and his parents have finally kicked him out of the house. Penniless and destitute, he travels to his grandmother Hinata's inn, hoping she'll put him up until he can get into Tokyo U and fulfill his promise with his childhood sweetheart (whose face he can't even remember). Unfortunately - or perhaps fortunately - it turns out that the inn is no longer an inn... it's an all-girls dormitory, as he discovers in his typical blundering fashion by grabbing an eyeful and more of every girl in the place! Narusegawa Naru, a fiery-tempered high school student and the first victim of Keitarou's lewd bungling, wastes no time doling out brutal punishment and preparing to kick him back out to the street. But wait! A letter has come from grandma Hinata, and Keitarou is to be the dorm's new live-in manager! Is this a blessing from heaven, or has he been cursed to a living hell?
Both involve romantic comedies, with a pretty, perfect female lead and many other girls in love with a single ordinary boy.