Adachi Yuudai

"'I'm sick of seeing heroes cut down like grass.'""-Adachi Yuudai to Class 1A" Adachi Yuudai (足達雄大), also known as Portal (ポータル), was a former hero student turned villain. He was the primary antagonist of the Portal Arc. He made his first appearance as the Residence Advisor (RA) for Class 1A after they were moved into the dorms. His goal was to change the hero industry so that no students died the way his teammates did during his internship and to ensure that the corruption within the system was eliminated. He looked towards the villain Stain for inspiration, which eventually led to his downfall as he turned towards violence to reach his goals.

Appearance
Yuudai was slim and bony and of average height. He had short pink hair, pale skin, and purple eyes that have bags under them; he wears rectangular glasses. Yuudai had scars on his cheek, neck, and most of his torso and arms from the attack that killed the majority of his team. He had a perpetual frown on his face.

Notably, after he went villain, he continued to primarily wear his civilian clothes even in combat, with the exception of later a belt that held his hero tech.

Early Life
Yuudai was born to Adachi Sen and Adachi Sakura on October 19. Sen died before he was born as a result of an altercation between himself and a drug dealer. Sakura neglected and abused him growing up. Yuudai focused on his quirk as a way to cope, fine tuning it and finding new ways to use it. At thirteen, about to turn fourteen, he applied early to U.A. and was accepted. He quickly became close with Nii Makoto.

Team Four
After making it into then-Class 1A, Yuudai quickly achieved his Provisional Hero License. During his first Sports Festival, he ended in 3rd place. During his first year, the school tried out a new internship arrangement where students were placed in teams of three or four under various heroes. He was placed in Team Four with Nii Makoto, Onaga Hana, and Kitamura Noa, with Hana as the designated team leader. At first, Yuudai butt heads with Noa a lot. He began to date Nii Makoto as well as crush on both Noa and Hana. With the help of Cementoss and Makoto, he emancipated himself during his second year.

During a team exercise during their second year, Team Four noticed a small-scale crime occurring nearby and decided to step in. Too late, they realized that they'd been caught in a trap and Makoto was tortured to death in the field. Hana died in the hospital soon after and Noa was injured severely enough that she would have to retire from heroism and committed suicide. Yuudai was left the sole survivor of his team. He later learned that Endeavor could have intervened but had chosen not to; from there, the seeds of his hate were sewn.

The Beginning & Defection
During Yuudai's third year, he threw himself into his work and began trying to figure out how to transform the hero industry to ensure that no students died in the future on internships. The longer he worked, the more disillusioned he became with the state of heroism.

He was officially expelled after breaking the gag order on the fight between Iida Tenya and Hero Killer: Stain.

Abilities
Overall Abilities: Despite a quirk that initially seemed weak and a impoverished, difficult upbringing, Yuudai's sharp mind and constant honing and development of his quirk allowed him to push and pull his abilities into new realms. Previous users of Doors, such as his father Adachi Sen had only been able to use the quirk to 'hide' in or teleport to seemingly random places. Yuudai experimented intensely with his quirk, allowing him to unlock its true potential: teleportation.

Keen Intellect: Arguably his strongest tool, Yuudai's intelligence and creativity allowed him to utilize his quirk in a myriad of powerful new ways.

Networking: Yuudai had contacts with almost everyone who was anyone in the villain and vigilante scenes as well as many heroes, allowing him to create a massive database of fights, heroes, villains, vigilantes, and quirks as well as create ties and collect favors from various people in the underground community.

Hacking: Adachi Yuudai had a fair amount of hacking ability.

Quirk
Doors (扉 Togira) is an Emitter type quirk. Yuudai can create a limited amount of doors from scratch; these doorways are more fragile but give him more precise control. They must go to somewhere Yuudai has been before and can clearly picture. They require the most energy and concentration but once in existence correctly, he can manipulate them as he pleases. They degrade and must be recreated over time.

Yuudai can also 'steal' doorways. He can only store a certain amount  before they get unstable; too many and they'll become unstable and potentially 'glitch'. Theoretically, if a glitch was bad enough,  he could  be scattered into the fabric of space and time or torn apart.

Trivia

 * Yuudai is a Libra
 * He was born in the Year of the Ox
 * Initially, Yuudai was developed as a tired, overworked Residence Advisor with a water quirk. He later developed into a villain thanks to an off-hand comment from one of the founders of the server.