As it suggests, the love interests of the protagonist have to be younger than the protagonist. However, it is only used when the age difference is quite significant, and either the physical/mental aspects of this difference gets some screen time.
I fell in love. Her name was Shirasaki Yukino. I could only look at her from a distance. However one day I heard that she already had a boyfriend. Even if I love her, I can’t have her. The devil sent me an invitation. I can make her mine!
Chen Rui, an otaku from earth, is reborn into a human body in another world, who falls into the legendary evil, brutal world of the devil called Mozu where humans are treated as food. He has to survive while facing horrors of the devil, violent dragons and a variety of powerful enemies by depending on a strange super system chip and his wits. Surrounded by Devil’s beauties such as black-bellied lolita princess, cold queens, violent dragons, charming poisonous devils … Wanting to live in the Devil’s world is hard! Wanting to live in the Devil’s world as a human is harder! Wanting a human to be the devil’s son-in-law is hardest! Let us see how a small otaku uses power and strategy step by step starting from an ordinary human to writing a legend as the devil’s greatest son-in-law.
Yang Ming is an underachiever in high school. He skips class to shoot pool, cheats on his exams and gets into fights. However, by a twist and turn of fate and luck, he obtains some high-tech contact lenses that give him superpowers and dramatically change his life. As his journey unfolds, he battles against society’s big guns and attempts to bring justice into an unjust world. Along the way, he has many interesting and romantic encounters with the ladies who are charmed by his character. How will he use his superpowers? Will he be able to overcome evil and bring justice to the world?
After a tear in reality pulls Kagari Shuya into a white room he discovers a futuristic interface for reincarnating in a different world. After looking through the different races and skills he unlocks a new race, Lucivault, a type of vampire with none of its characteristic weaknesses. All set to start his life in a new world, Shuya is confused to discover that he is enveloped in darkness. As it turns out something went wrong when he was transported and instead of appearing where he was supposed to, he appeared in an underground cave. Shuya faces untold dangers, runs for his life, before finding his way out of the underground world. After escaping he meets his Shishou and begins to learn to fight with a spear. There is also a cute black cat named Rollo.