Level 5

Level 5 (超能力者 (レベル5) ) is currently the highest esper level to be accomplished in Academy City. Only seven out of the 2.3 million students participating in the Power Curriculum Program have officially achieved this rank, indicating the level of difficulty involved in reaching it.

All of the currently known Level 5 espers have been attributed a nickname that is either the name of their esper ability or related to it. Currently, Accelerator is known solely by his nickname.

Promotion to Level 5 is approved by the Academy City Board of Directors.

Characteristics
Level 5s are espers who hold tremendous amounts of supernatural power; their talents far exceed that of other espers, including those with similar capabilities. The abilities of Level 5s are so strong that their primary applications are banned in the Daihaseisai.

Because the Power Curriculum Program is part of Academy City's curriculum, the strongest of its espers are most likely to be honor students. This is exemplified by both Mikoto, who is one of the top students of Tokiwadai Middle School, and Accelerator.

Moreover, Level 5 espers have specialized research facilities that are dedicated to them; for example, Accelerator being part of the Special Ability Institute, Dark May Project, and many more. They most likely get paid with the most money amongst their other esper peers as part of the curriculum's payment program for the espers as being part of the experiment.

Also, it seems that Academy City views Level 5 Espers (and others in general) as a threat, due to the fact that their developing minds can make them act based on emotions rather than logic. In order to rest easy, they have created Rensa, a cyborg that can use the abilities of the #1 up to #6 in order to deal with them in the case they decide to go against the city, and she supposedly can defeat all seven of them.

The ranking of the Level 5s is dependent on the worth of their abilities to the ongoing researches rather than based on the relative strength of their power. Their counterparts are the Saints from the magic side.

Personality
A particular object of notability of all the Level 5 Espers is a recurring instance of mental instability, be it comedic or serious. Mikoto, the first Level 5 seen in the series, has a comedic obsession with defeating Kamijou Touma, although she has been referred to as the sanest one out of all the Level 5s. Sogiita Gunha believes himself to be an ally of justice and purposely acts in accordance of superheroes in fiction. Accelerator, Kakine Teitoku, Mugino Shizuri, and Shokuhou Misaki all demonstrate more sociopathic or psychopathic tendencies with the willingness to hurt people on a whim, though this may be more related to their background more than anything else. However, both Accelerator and Mugino have become less violent lately because they feel guilty about all the harm they've done. Misaki has also demonstrated that she does care about her friends and is willing to go out of her way to save them.

Due to this, only Mikoto is the one apparently competent enough to be used as a marketing mascot or demonstrator for Academy City. Even then, it is not unheard of for any of the Level 5s to be requested for demonstration.

That said, the essay The Wall Between Level 3 and Level 4 from Toaru Majutsu no Index no Subete seems to reject this premise, stating that gaining high level powers like Accelerator and Mikoto did is the result of having strong minds and firm ideologies and principles.

In addition to this, many of the Level 5s are not on good terms with each other, although they would still sometimes form alliances if the situation called for it.

Level 5 Candidates

 * Hokaze Junko, Level 4 Rampage Dress — Stated to have the potential to become a Level 5, as the researchers of Ideal detected within her powers, but her subconscious defensive instincts prevent her from drawing out her full power.
 * Mitsuari Ayu, Level 3 Mental Stinger — In the past, she and Shokuhou Misaki were roughly equal in power and Tree Diagram calculated that both had the potential to reach Level 5. However, only one could do so while the other would plateau and improve no further. Following the conclusions of the Parameter List, the higher-ups of Academy City decided to devote more resources to Misaki's development and kept Mitsuari as back-up in the event of the former's death, but permanently stuck at Level 3.
 * Musujime Awaki, Level 4 Move Point — Was a Level 5 candidate two years prior to the current year of the timeline. Her school, Kirigaoka Girls' Academy, was actually pushing her to become a Level 5, to make her the strongest Teleport esper possible, but during one of these trials, she teleported her leg into a wall, severely injuring herself, and giving her a trauma that now prevents her from teleporting herself more than 2 or 3 consecutive times without getting sick as well as requiring 3 seconds to do it. Her trauma also stopped her improvement completely, meaning her path to becoming a Level 5 has been closed. According to the author, her power at Level 5 might be something similar to Almighty Thor.
 * Takitsubo Rikou, Level 4 AIM Stalker — Has the potential to become the 8th ranked Level 5, which would enable her control over AIM and related Personal Realities.

Trivia

 * When discussing the existence of Anna Sprengel with Kamijou Touma and Accelerator, Aleister Crowley uses the term "#0 Level 5" as comparison, showing the mystique and persuasive ability of "a missing superior rank". As it was only an example, it is unknown if the 0th Level 5 exists even after Anna Sprengel was proven to be real.