Takeshi comes across a girl in distress on his way to Kendo practice, and as a true hero he does so but ends up receiving more than what he bargained for. The girl wakes up from her unconscious state, accidentally giving Takeshi the ability to perform magic powers. He soon finds out that he lives between two worlds, the one he is aware of, and the one where magicians have big ambitions to live alongside non-magicians. Along his journey he encounters other magicians that he must build relationships with in order to defeat the evil Ghost Trailers, who are magicians willing to harness their power violently and assert superiority over humanity. Now Takeshi must prevent the Second Great Magic War from taking place, while learning more about himself throughout his experiences.

Takeshi is a lot like Arata where he's thrown into a world where he must come to terms with, and along the way build relationships with other characters to ensure the world's survival. They initially have no idea what they're being introduced to, since the two have a random encounter with a girl who pretty much changed their entire state of being. Once they realize that their world is in peril, they start to take their new roles more seriously and help to prevent terror from consuming the world.

The world that Issei lives in is one full of perverted fantasies, peeping on women, and dreaming of running his very own harem. Most of his plans seem to be going well when he suddenly is confronted by a girl who asks him on a date. The unfortunate side to this is that the girl is actually a fallen angel who sees the opportunity to kill Issei on the spot. Things turn around once again for Issei when he's given a second chance at life but this time under the order of Rias Gremory, a top-class devil who uses him as her servant and recruits him into the Occult Research Club. Issei must now come face to face with a world that is filled with constant danger at every turn, battling demons while enjoying the ecchi lifestyle that has become his harsh reality.

While both Issei and Arata are the victims of a relationship gone south, the two somehow end up in a position that they never intended to be in. Issei desired the harem life, but not forced upon him in such a way that he now must fight for his life. Both shows are full of ecchi moments and dirty jokes as both protagonists must realize there's no turning back, so their only option is to work alongside these well endowed females to make a change. A lot of fondling of breasts are seen throughout each show, which act as a motivator for each protagonist to perform better under extreme pressure. The two in the end live a life that initially was off putting, but now have a lot more purpose due to their attractive surroundings.

Main protagonist Toujo was asked by his father if he'd like a little sister in his life, which initially was his dream but not the way life had planned it out. On top of that random question which threw Toujo into a state of panic, his father then mentions he will be getting remarried. The story of Shinmai Maou no Testament follows Toujo, who now must come to face a harsh truth when he finds out the true form of his two beautiful step sisters.

As you can tell from the premise of the story, both Toujo and Arata face a similar fate in which the two must embark on a dangerous journey, and learning new responsibilities along the way. They both find themselves in a harem scenario where they're surrounded by powerful females who use their ecchi behavior to keep the boys in check. All of this course doesn't come without some comedy, as both shows despite having to deal with an evil enemy, have a lot to laugh about especially when Toujo fumbles about trying to adapt to this new world.

Ryuu Yamada enrolls into Suzaku High School, in hopes that he can start anew and lead a productive school life where no one would know of his troublesome past. Ryuu has reverted to his old ways due to his new surroundings becoming a bore, until one day Ryuu encounters the beautiful Urara Shiraishi. A misstep causes them to fall down the stairs, ending in an accidental kiss, and the two soon discover they can switch bodies with a kiss. Coming to terms with their new power, Toranosuke, a student council officer and sole member of the Supernatural Studies Club, takes them under her wing. Soon joined by Miyabi, the group unearths the legend of the Seven Witches of Suzaku High, seven female students who have obtained different powers activated by a kiss. Their new quest is to now discover the real identities of all the witches.

Ryuu just can't seem to get a break in his life until something enters his life without warning, throwing him into a whirlwind of new experiences. Similar to Kasuga, the two find themselves dealing with 7 females who all have extraordinary powers, and must use them to extinguish evil from the world in which they live. Both introduce harem into the story with Ryuu's life focusing more on romance, while Arata deals a lot more with perversion. They both must adapt on the fly, and learn to understand the truth behind all that's happening around them, changing their perspective on life forever.

One of the more recent harem action anime is Saijaku Muhai no Bahamut. We follow Lux, a former prince of the Arcadian Empire that was overthrown via a rebellion five years earlier. By accident, he finds himself in a female dormitory's bathing area, observes the kingdom's new princess Lisesharte in her natural state, resulting in her lashing out. After this embarrassing ordeal, she then challenges Lux to a Drag-Ride duel. Lux was labeled as the strongest Drag-Knight, but now he's known as the "undefeated weakest" Drag-Knight because he refrains from attacking in battle. After his duel with Lisesharte, Lux ends up attending the female-only academy that trains royals to be Drag-Knights.

Lux just can't seem to get himself out of trouble, always running into obstacles that he must somehow overcome. Fortunately for him, he gets to live out his life with beautiful girls in a harem style environment. Lux is picked on by all of them, but eventually must put all insults aside in order to reclaim his title as the strongest Drag-Knight. All of this course doesn't come without some ecchi to really liven things up, and so throughout the show you'll see skirts lifted, chests exposed, and a lot of moaning and groaning to keep you glued to the screen. The show definitely showcases a large handful of action to go along with all of the “sound effects” that you'll hear throughout, and it truly brings the show to life in a great way.

Strike the Blood stars Kojou Akatsuki, as his life as an ordinary high school student in the Demon District of Itogami Island, comes to a halt after a fateful encounter bestows him with the superhuman abilities of a vampire. He is then catapulted into a myriad of uncertain events, and discovers that he's the fourth primogenitor, who many have said to be a legendary vampire who wields incredible power. The Lion King Organization is ordered to call upon apprentice sword-shaman, Yukina Himeragi, to survey him in fear of Koujo's destructive powers, and should he become a threat, to kill the boy immediately. The two must now form an unlikely alliance as Kojou comes to terms with his abilities and they both struggle to protect the city from various emerging chaotic forces.

Kojou is granted a power which he'd never imagined possessing in his entire life, and must now team up with hot girls to battle the forces that oppose them. Both Arata and Kojou didn't necessarily wish for these events to happen, but end up in a pleasing scenario with a bunch of powerful women as their allies to fend off evil. Whenever the two are confronted by the girls, flirtation always transpires which leads to nosebleeds or someone getting punched in the gut for their perverted behavior. Both shows offer up a great amount of humor with Kojou being the more dry of the two, while Arata just doesn't care what he says and wishes that he could see more boobs in action.