|Height||172 cm (5'8")|
|Weight||57 kg (126 lbs)|
|School||Kunugigaoka Junior High School|
|Japanese Voice||Ryota Ohsaka (Anime) |
Yūto Uemura (OVA)
Daisuke Motohashi (VOMIC)
Isogai has somewhat spiked black hair with two small hair antennae at the top and brown eyes. In addition to his personality, Yūma has been described as being very attractive and is one of the most attractive male members of Class 3-E.
Isogai is a kind, cheerful, and reliable person. He is modest, not at all boastful, and helpful. Isogai has been noted to have good leadership qualities and personal virtues, and due to that he's able to see all the individual strong points in his classmates. Because of these traits, he is considered to be an ikemen, which not only means handsome, but can also imply a flawless personality.
Isogai has stated that he comes from a poor family and has siblings and a sick mother, both of which he takes care of and as a result has a part-time job. Unlike many of the students in Class E who landed there due to poor grades, he was put in there for violating school regulation which states that students can't have jobs.
Out of all the students in Class E who aren't primary perspective characters or primary characters in general, Yūma is among the most seen. While his official introduction wasn't until Chapter 90, his first notable appearance was during the Finals Arc where he was the rival to Teppei Araki in Social Studies.
The Athletic Festival Arc is where Isogai makes his formal debut. It starts out in Chapter 90 where a few of his classmates are visiting him at his part-time job. While Isogai is attending to two regular customers, they note that he truly is an ikemen (with one of them, most likely Okajima, noting they want to kill him for it). They then began to basically state how incredible their leader is at everything and Korosensei, who was revealed to have come there for some honey toast, ask them if they're bothered by Isogai no matter how much of an ikemen he is. They say no and he asks why is that and Maehara just simply says that Isogai is just a nice guy, earning the agreement of his peers. Then, a few more customers come in who are none other than the Five Virtuosos who found out about Isogai's part-time. One of the regulars come to Yūma's defense and Ren Sakakibara charms her and tells her it's a school matter so they'll take it outside. Outside Isogai begs Asano to keep it a secret since he needs the part-time and Asano states that he would also like to as well, but on one condition: Isogai and the rest of Class E show him their fighting spirit at the athletic festival's Bo-taoshi match.
The next day Class 3-E is discussing this and note the unfairness of the entire setup. Isogai, not wanting anything to happen to his companions, states that he'll shoulder all the responsibility. This elicits angry remarks and some students (particularly Karma and Nagisa) through stuff at him. The class calls him an idiot for thinking he'd be alone in this and Maehara tells him to not think too much. He slams an Anti-Sensei Knife on Yūma's desk and says it'll be easy beating the nerds in Class A at bo-taoshi. Other students then jump in and agree, saying that this match will be a good chance to get back at them for all they've done to them. Isogai is touched by this and declares that they're doing it.
It's the day of the athletic festival and while his classmates are going through their events, Isogai is working on the strategy for the bo-taoshi. As Class E show their hidden strengths, Korosensei says that if only that unpredictability were used by assassins and that the foundation of strength, balancing abilities, kinetic vision, and sense or which have been strengthen through assassinations will show in non-everyday competitions. He also says that in such ways those individual personalities become a weapon and how that will be capitalized in the bo-taoshi will depend on Isogai. While the students of Class E decide to focus on the final bo-taoshi, they find out what Asano had been planning and his true goal which were in the form of four huge foreign 14-15 year old top sportsmen. As Asano is talking to two of them, Isogai starts to feel insecure as his abilities aren't anywhere near Asano's. He starts to feel conflicted and begins worry about his team. Korosensei tells him that in society there's a limit to one person's abilities and in terms of the ability to lead and fight with friends, he surpasses even Asano and even when he falls into a pinch, everyone will fall with him and fight and that is his personal virtue. Korosensei then said that he's glad that he was able to be Isogai's homeroom teacher. After that it's time for the bo-taoshi to start and both teams line up. Class A is given the advantage once again by being allowed to wear headgear and long sleeves, but Class E doesn't let that deter them as they enter their initial formation: the Ultimate Defense Form.
Both classes battle it out fiercely during the match. During one particularly tight spot, Isogai thinks back to a previous lesson about Hannibal of Carthage and how he led his small army to victory through wit and thinking outside the box. With that in mind, he leads his team and the Class A students who are chasing them to the stands since there was no rule saying they had to stay inside the field. Class E continues evading Class A until finally Muramatsu and Yoshida appear, revealing that being knocked out earlier had been a ploy. Isogai then tells everyone they're done running and calls for the next formation, "Speed of Sound." Those of Class E who were on offense rush toward Class A's pole. With all them in they proceed to corner Class A and shake the pole down. As a last resort, Asano starts attacking and at some point strikes down Isogai who reveals to have used that to add four more students to the mix. Finally, Isogai calls for their secret weapon, Itona and launches him six feet in the air onto the pole and bringing it down giving Class E the win.
After the match, as everyone is cleaning up, a few underclassman congratulate Isogai. Eventually, Asano shows up and Maehara asks him if he's going to keep his end of the bargain to which he states that he doesn't lie nor use underhanded methods like they did. Isogai comes up and congratulates Asano on his command and tells him they should have another match some other time. Asano simply walks off and gives a snide remark but Isogai isn't bothered by it in the least. While everyone calls him a sore loser, Takebayashi states that Asano has been going through a lot like Isogai the latter of who says that his situation doesn't even compare. Even so, having everyone get together to help him made him grateful that he was poor. After that Nagisa notes that Isogai isn't flashy like Asano is nor is he out front or top, he's right there next them, an assassin and ikemen. The arc then closes with Isogai begging to take home the leftover bread from the bread race.
Knifework: Isogai excels in knifework and is considered the best out of all the boys in Class 3-E.
Marksmanship: Isogai is ranked second for marksmanship of the boys' side.
Social Studies/Geography: Yūma is ranked 1st in the school for Social Studies.
Other Skills: Yūma is known to have excellent reflexes and is good at sports. He has good leadership skills.
Isogai and Maehara get along well. With their excellent reflexes, the two can become formidable opponents when teamed up.
- His favorite subject is Geography/Social Studies while his least favorite is Biology.
- His hobby/special skill is tennis.
- In the tankobon extra it was stated that his classmates want to yank the two antennae sticking out at the top of his head.
- He was called "Poor Committee Member" during class 3-E training using code names.
- In the popularity poll of Volume 12, he was the highest ranked student outside the main trio, at 6th place.
- In the tankobon extras, his statistics were listed as:
- Physical strength: 4.5
- Mobility: 4
- Close-range assassination: 5
- Long-range assassination: 4.5
- Academic ability: 4.5
- Characteristic skill: 4 (all-purpose adaptability)
- ↑ Assassination Classroom Manga: Chapter 5, Cover
- ↑ Assassination Classroom Manga: Chapter 24, Page 15