Sehyun Seok

Sehyun Seok was a lawyer and a well known criminal prosecutor. He was an honours graduate of Minerva Academy's law department.

Unknown to his family and friends, he was actually the infamous vigilante known as Nabi. His crusade on the Underide's gangs ultimately made him an extremely wanted individual amongst the members of Minerva's criminal underworld. As of the beginning of the story, he was killed by Veragreen.

Appearance
Sehyun was most notable for his hair which had strands dyed light blue. He has been criticised by his friends as looking like a "K-Pop Idol."

He has a blue butterfly tattoo down the forearm of the left arm.

As Nabi, he wore a white mask.

Personality
Sehyun was extremely confident and cool-headed, something which his best friend Lev attempts to constantly imitate. Yet, while Lev was socially awkward, Sehyun was able to quickly make friends due to his natural charisma. He developed a skill for cunning manipulation.

Powers and Abilities
Sehyun never showed much of his combat prowess in front of others, but as Nabi he was believed to be one of, if not the strongest fighter of recent times. He has studied Kickboxing as well as several Korean martial arts such as Hapkido and Taekwondo

Weapons
Nabi was often seen wielding a shashka by the name of Lyudmila. Lyudmila is a top of the line, government produced experimental weapon; the first in the world to be made from Cerafex Steel at a level 5 purity, the highest ever recorded. As such, Lyudmila is able to cut through almost anything with one slash, is extremely durable, and is even resistant to degradation due to high speed transport.

Epithet
Sehyun's Epithet, Lethe, was a very unnatural one. It had the ability to manipulate memories, including absorbing, deleting, and editing memories from other people. Doing so requires the person to be either unconscious, or at least disabled enough to be unable to retaliate. However, a strong mental willpower has been known to be able to resist Lethe.

The most important aspect of Lethe's abilities was that it bent the rule that one person could only ever possess one Epithet. Lethe's ability to absorb memories, meant that Sehyun could access those memories and from them, draw out the victim's Epithet. While he could store up a large number of Epithets and use any of them at any time, it comes with two major drawbacks. One being that the mimicked Epithet will be weaker compared to the original and the other being that storing so many memories takes a very large toll on Sehyun's mental health. After storing countless Epithets, Sehyun had numerous and constant headaches as well as displaying signs of Dissociative Identity Disorder.