|Date of Birth||June 6, 11:29:35|
|Team||Capturing Spirit Squad|
|School||Maijima Private High School|
|Novel Debut||Chapter 1|
|Manga Debut||Chapter 1|
|Anime Debut||Episode 1|
Keima Katsuragi (桂木 桂馬, Katsuragi Keima) is the main protagonist of The World God Only Knows series, written and illustrated by Tamiki Wakaki. He's known in the gaming world as the God of Conquest (落とし神, Otoshigami) for being extremely skilled at conquering every girl in dating sims. He's known in his normal life as Otamegane (オタメガネ), a portmanteau of "Otaku" (オタク, Nerd) and "Megane" (メガネ, Glasses). "Otamegane" can roughly be translated to "gloomy geek with glasses", referring to his silent and extremely cold behavior. Keima is obsessed with games, to the point of closing himself up in his own room and playing for three days straight, just to make it for his "deadline" on the Internet. His main catchphrase is "I can see the ending!"
Keima has brown hair and eyes, wears glasses, has a bed hair sticking out and usually has a PFP in his hands. His uniform varies according to season. When he's not wearing it, he wears a long-sleeved shirt with a white collar and pants. He's also forced to wear a black (purple in anime) guillotine collar on his neck, proving he made a contract with Hell. Keima is also shown to be quite handsome, especially without his spectacles. This is apparent, as when Keima ever approached a capture target, most of them tend to be flustered. And Ikumi Yoshino from the light novels even said that he looked like a "a rich kid hikkikomori! Or something like that." When he cross-dressed, he was able to enlarge his pupils, thus making himself look like a girl and even at that, he is able to attract boys into flirting with him (much to his annoyance). He also seems to be able to transform his face to a less attractive one when he doesn't want to be identified.
Keima also owns a light-blue and dark-blue striped Yukata along with a blue slash along with wooden slippers.
At the start of the series, Keima is completely detached from reality, showing absolutely no interest in any real girl, even pointing out that they are flawed and claims he is in no way sexually attracted to "3D girls" and sees such thoughts as below him. He hates virtually everything from reality, even himself. As a result, he takes refuge in his 2D world.
Keima is an avid gamer and is extremely devoted to finishing his games. When challenged with a bug in a game, Keima tried every single option in the game throughout seven hours straight, tiring even Elsie. He becomes very attached to the heriones and firmly begins that there is no such thing as a bad herione, only bad games.
When talking to people normally without altering his personality, he is generally cold and distant. If he is paying attention to his PFP or any other kind of game, he will even take no notice of other people around him unless called vigorously, physically abused or appealed to.
He seems to take the concept of making mistakes extremely difficult, as shown when he got a 99% on his English test instead of a 100% simply because he was distracted when he was tutoring Ayumi, Chihiro and Kanon. Also, this is extremely obvious during the point in time when Kanon had been stabbed. He seemed to take the incident very seriously as compared to most other things, and even blamed himself for her being targeted.
Keima would also change and alter his true personality to match and make his conquest targets appeal hence, making the capture easier. The instances when he did not alter his personality at all is his capture of Chihiro and Tenri.
As the series progresses, Keima slowly changes his view of the real world and Keima has also gotten more into devoting time and energy to his conquests. In the beginning, he was often very reluctant to capture girls and would also be quite flustered whenever they showed affection to him. But as time goes on, he's more precise whenever a runaway spirit shows up, devoting time and energy into it while holding his composure even during the kissing.
Recently, when Kanon was assaulted, Keima entirely stopped playing his PFP and is very devoted to searching for the goddesses. Furthermore, Keima has also began to show a much softer side shown that when he rejected Chihiro, Keima gave genuine faces of sadness and grieved. As of chapter 189, Keima's perspective of the real girls has changed, shown most evidently when he shed tears and even apologized to what he had done to Chihiro.
Keima also seems to be accepting reality more saying "There is no difference between the real and the virtual. I'll aim for the best ending". However, he still seems to believe 2D girls to be superior.
Keima remains faithful to his "2D girls", and in particular, to Yokkyun and immediately after assembling all of the goddesses, Keima shut himself in his house for five days straight to play his games.
Despite the fact he plays video games in class, Keima is a top scorer in every subject. When he was scolded by his English teacher Ichirō Kodama because of his gaming habits, he reasoned that everything would be fine as long as he aced all his exams, and then proceeded to do so, demonstrating a great academic ability. It is shown that he applies the same analytical skills he utilities to "capture" girls when studying. This method was proven effective when he flawlessly predicted the questions on the upcoming English test, basing himself on the teacher's personality and the examination extent.
Keima can multi-task with unflinching accuracy. He has been shown to be able to operate several different video and computer games at the same time with extreme ease and regularity. He can even place his full attention to each screen, becoming "emotional" whenever a screen has an emotional scene. His room is set up to allow him to play up to eight different video games at once. He also has an extensive collection of video games and systems, even those that goes as far back as the early cassette based computer games of the 70's and 80's. Keima has made a point that anything less than several games at once leaves him unchallenged and unsatisfied. The diversity of the games he owned and conquered also contributes to him excelling at many other non-galge games like shōgi.
Keima is also a fast learner, being able to beat Haqua in her New Hell-only game multiple times despite the latter claiming to have never lost for the past 100 years.
In an omake, it is said that Keima has modified his PFP, granting them never before seen abilities that normal PFPs don't possess. This may hint that Keima is also good with technology.
During captures, he is shown to be able to use his vast knowledge of galge to help him. Although some of his techniques backfired, Keima has always managed to get to the roots of the girls' emotional problems, showing great adaptability. His skill in conquering girls may be inherited from his father, as his father was able to "conquer" Mari who used to be in a biker gang. Keima is also very organized during capture operations, sometimes withstanding days and weeks of tedious menial labor just for the sake of setting up the needed scenario.
Keima is also a gifted actor, being able to adjust his real personality between every capture, usually altering the personality presented to something he knows will appeal to the girl in question. For example, he acts really concerned, supportive and interested in Kanon's problems while for Sumire he acts like the ideal, polite employee. This does not apply as much with Chihiro and Nanaka, neither of whom he was actually intending to get to love him. Very few people, notably only people who are very close in relation with Keima, can ever tell if Keima is lying or forcing himself to act, one such person being Tenri.
Keima however, does have weaknesses that has made his capture in-real-life harder and more difficult:
- Ordinary girls like Chihiro or Asami with no clearly defined traits. Without a defined trait, Keima would have a hard time altering his personality that best suits for the conquest.
- Daydreamer-type girls like Tooru Amami, since they operate outside logic due to conflicting personalities and all of his technique is based on said logic.
- Aggressive girls like post-capture Yui. He plays games where he is the player chasing after girls. If a girl chases after him, being inexperienced in such a situation, he tends to be extremely flustered.
- Uncooperative-type of heroines who do not do what Keima said or predicted. Examples include how Chihiro who does not follow suite with Keima's plans during the Sports Fest, and Akari, who was very persistent in using Keima for her 'kissing project'. Yui also briefly displayed this behavior during her conquest before Keima cross-dressed as a girl.
In terms of physical abilities, he has been shown to be from average to horribly unfit. This is due to his obsessive gaming habits, leading him to ignore the outside world and game in his room for extended periods.
Keima is also capable of doing sport activities such as baseball batting if it has anything to do with capturing 2D girls, such as a girl character on a monitor who reacts if the batter manages to hit a target with the baseball. This is due to the above example classifying (barely) as a galge.
Keima has demonstrated to be able to withstand being electrocuted (by Kanon), kicked (by Ayumi), punched (by some other girls) and even attacked relentlessly (by Nora) without sustaining any major injuries, showing great physical endurance, which even seems to extend to his PFP.
Finally, perhaps as a gag, Keima has shown even supernatural abilities. For instance, when he heard that there are going to have new games, he magically floats to the game store. Keima has also shown the ability to nosebleed whenever he wants, shown in the Hinoki Arc.
He has been shown to be capable of running quickly for extended periods of time while excited, as shown when he had just discovered Yokkyun in the anime, leading him to run from his home to school, while Elsie struggled to keep up with him. He was also able to quickly speed across rooms.
Keima apparently is good at making coffee and cleaning. His coffee is so good that his classmates claimed that regular made coffee was dirt in comparison to Keima's coffee. He claims that this is because of his pride of his family running a cafe. Elsie commented that he cleaned the floor so well that he could even teach her, one who had cleaned for several decades in Hell.
Keima is also capable of carrying multiple PFPs, even when there is notable no place to hold them on his body or clothes. This leads to student-teacher Jun Nagase to think that Keima was a magician of some kind.
Ten years before the start of the series, when Keima was seven years old, he and his childhood friend, Tenri Ayukawa, were trapped in Akanemaru during a field trip organized by their elementary school when an earthquake broke out. Keima and Tenri would then go inside Akanemaru and eventually, there will be a second earthquake that would have caused a large boulder to hit Keima's head, erasing most of his memories about Tenri and her family for ten years.
It is then, when Keima was unconscious, the earthquake released a large number of the present day spirits from their seal. A goddess named Diana would then possess Tenri and, using her powers, carry Keima to the now Old theater from Maijima Private High School.
By the time Keima woke up, the school teachers were worried sick and his old home was completely destroyed by the earthquake. Keima's grandfather, Denma Katsuragi, would then give up his pottery shop to Keima and his family and Mari later turned it to a café.
Keima would then continue on his gaming ways, soon enough being enrolled into Maijima Private High School.
- His first name is derived from the term "gamer". Keima's name could have also come from the names of his father and of his grandfather: Keiichi and Denma, or also from the name of his mother Mari. The kanji “Kei” & “Katsura” in Keima's name are the same, but have different meanings. Kei is used in the name for knight in Shogi and Katsura is a Japanese Judas tree.
- "Keima" (桂馬) is also the name of a shogi (Japanese chess) piece, which is similar to the knight in international chess.
- In the one-shot version of Kaminomi, his name is "Keima Imai" and he is 16 years old, not 17.
- He dislikes sweets and aggressive heroines (mostly Yui).
- His email address was shown, on his PFP, to be "email@example.com". "zumcities.co.jp" is a nonexistent site, making the address a fake one.
- During Keima's brief stunt as an actual girl, he began to play otome games (games where the player character is a girl making guys fall in love with her, as opposed to other dating sims), a fact that caused him significant anguish and prompted a comedic scene depicting his will and testament. Yet, he was able to understand the girl's role in dating sims and learn from it.
- His drawing skills are famously bad, to the point of being mocked by even Elsie.
- Keima can use his God of Conquest Mode, which allows him to use six different game consoles to play six different dating sims at once. He can play more games simultaneously if he has more game consoles.
- He likes to present things in a numerical manner, one example being when he says that he has seen a certain type of girl 300 times in games.
- Keima's spectacles is a reference to Wakaki Tamiki's earlier work, Holy Crystal Albatross, being that the heroine Asakura Sakura has the same kind of spectacles.
- Keima dislikes being touched, as he does not want to be touched by anything of the real. As a result, he is not used to the physical contact and has displayed this throughout the series with physical display or verbal cries of "Don't touch me".
- Keima shares his birthday with Asami and Ikumi Yoshino.
- Keima does show that he cares for the girls he has conquered. A few cases include when he kept the "promise" he made to Chihiro and the expression he made after he met with Minami during the reconquest arc.
- (To Elsie) "Hmph! I have lived in the gaming world for 10,000 years!" 
- (Either to himself or Elsie) "I can see the ending!"
- (To Elsie) "I'll teach you something useful"
- (To himself) "Reality is just garbage!"
- (To Elsie) "I won't give in to the real!"
- (To Chihiro) "True, I've given up on the real world, however I haven't given up on myself. The world doesn't get to decide whether my life is boring, fun, or ordinary 'cause that's my decision to make. As long as I have the will nothing is impossible!"
- (To Elsie, while in Yui's body) "Otome games are interesting too! You should try them!" 
- (To Elsie) "Don't be upset because of what you can't do. Do what you do best, live as carefree and optimistically as you can, because some people aren't able to do that." 
- (To Diana) "It is my fault... that your power hasn't returned. I've been an especial burden for both you and Tenri... Unlike the other girls, you know more about what's going on, so... I'm truly sorry." 
- (Monologue) "If the ideal world can be found in a bad game, it can be found in the real world as well." (Anime only)
- (Monologue) "Chihiro, I'm sorry. I don't really mean...what I said that time..." 
|The World God Only Knows|
|Main Characters||Keima Katsuragi • Elucia de Lute Ima • Haqua du Lot Herminium • Tenri Ayukawa|
|Jupiter Sisters||Diana • Apollo • Vulcan • Mars • Minerva • Mercury|
|Capture targets||Ayumi Takahara • Mio Aoyama • Kanon Nakagawa • Shiori Shiomiya • Kusunoki Kasuga • Chihiro Kosaka • Jun Nagase • Tsukiyo Kujyō • Minami Ikoma • Rieko Hinaga • Sumire Uemoto • Nanaka Haibara • Yui Goidō • Hinoki Kasuga • Dokuro (Human) • Urara Shiratori|
|Minor characters||Mari Katsuragi • Keiichi Katsuragi • Miyako Terada • Izumi Ishikiri • Fujiidera • Ichirō Kodama • Morita • Hiyori Sakurai • Sora Asuka • Airi • Mobuko • Yuu Hatori • Yotsuba Sugimoto • Mai-High Delinquents • Okada • Yui's mother • Hiroyuki Ishigami • Yanagi • Shoutaro Shiratori|
|Novel characters||Tooru Amami • Asami Yoshino • Ikumi Yoshino • Shino Akuragawa • Aoba Fuse|
|Magi Kanon characters||Kozue • Bell Mark Atsume|
|Runaway Spirit Squad|
|Buddy Characters||Keima Katsuragi • Yukie Marui • Ryō Asama • Yuri Nikaidō|
|Buddies' Demons||Elucia de Lute Ima • Haqua du Lot Herminium • Nora Floriann Leoria • Akari Kurakawa|
|Other Demons||Cresta and Camry • Dokuro Skull • Fiore Loderia Lavigneri • Sharia Frey Amon • Lune • Gira|
|Equipment||Hagoromo • Detention Bottle • Sensor|