Shadow Ring

Shadow Ring (シャドーリング, Shadōringu) is the A-Class Rank 32 professional hero for the Hero Association, and a ninja from an unknown village.

Appearance
Shadow Ring's attire consists of a black ninja garb that completely covers her face and body. Underneath her garb she wears an eyemask and has dark hair put in twintails.

Personality
Shadow Ring appears to have a very reserved personality. She was visibly stunned by Flashy Flash's speed and admired his ninjutsu skills.

History
Shadow Ring trained at a ninja village. It was different from the one that Flashy Flash trained in.

Monster Association Arc
Shadow Ring is one of the heroes recruited to the Monster Association raid's support team. When the monsters ambush the heroes, she battles them alongside her fellow heroes. She mows down several monsters with her shurikens. A monster comes up from behind her and slices her head straight down the middle, but it's revealed to be a trap, where the real Shadow Ring them slices the monster's head clean off. She sighs in relief, when Flashy Flash compliments her movements, asking her in what village she trained. Shadow Ring replies that it wasn't the same as the S-Class hero's, and runs back into battle. As the second wave of monsters arrives and Rhino Wrestler attacks the heroes, Shadow Ring sprints up to him and strikes him with her ninjatō, but Rhino Wrestler shrugs it off, giving her a measly 10 points out of 100. Then, while Iaian holds Rhino Wrestler in place, Shadow Ring strikes the monster along with many other heroes, but she is blown away along with the other heroes.

After Rhino Wrestler is defeated and Atomic Samurai eliminates a large horde of monsters, Flashy Flash decides to kill a large group of them. Shadow Ring witnesses this and marvels at his amazing speed, noting she couldn't see him at all.

The hero support group fights off the remaining Monster Association forces on the surface as they escort Waganma to safety. Suddenly, Nyan appears monster attacks the group, incapacitating several of the heroes. The remaining heroes prepare to fight the monster. Green and Strange Binding Shell restrain the monster, and Shadow Ring and Feather try to take advantage of its apparent immobility and attack it with their clawed weapons. However, Nyan slips out of the bonds and swiftly defeats the two heroes.

Abilities and Powers
Being an A-Class hero, Shadow Ring is a skilled and powerful fighter. She is complimented by Flashy Flash for her combat skills. However, she is outmatched when against Demon-level monsters, as seen in her fight against Rhino Wrestler.

Physical Abilities
Enhanced Strength: Being an A-Class hero, Shadow Ring has rather impressive physical strength and is able to dispatch several monsters with ease.

Enhanced Speed: As a ninja, Shadow Ring is naturally fast, as she was able to react to a monster striking from behind her, replacing her head with a wooden plank and slicing its head off in an instant.

Enhanced Reflexes: Shadow Ring has very good reflexes, being able to react to a sneak attack from behind very quickly.

Fighting Style
Ninjutsu: Trained in a ninja village, Shadow Ring has demonstrated that she is proficient at ninjutsu.
 * Body Replacement Technique: Shadow Ring replaces her body with a block of wood to misdirect her opponents.

Equipment
When the topic of Paraphernalia was brought up, she claimed to be fully prepared for battle. Being a ninja, Shadow Ring presumably carries around stereotypical ninja weapons such as a sword, shuriken, kunai and more.

Ninjatō: Shadow Ring uses a ninjatō, a sword with a straight blade, black square guard and a black hilt.

Shuriken: Shadow Ring uses numerous shuriken to attack monsters from a distance.

Tekko-kagi: Shadow Ring uses a pair of tekko-kagi, a claw-like weapon in each hand.

Trivia

 * Shadow Ring is the first female ninja shown and the only ninja without a redundant name e.g Flashy Flash, Speed-o'-Sound Sonic, Hellfire Flame and Gale Wind. She is the also the first and only ninja shown that's not from the Ninja Village.
 * Yusuke Murata considered giving Shadow Ring an unexpected look underneath her ninja garb.
 * It's a Japanese trope based on the actual legends built up around historical Ninjas (probably also by said Ninjas, for whom misinformation was a great tactic). "Kawarimi" was a supposed technique possessed by the ancient Ninja that used misdirection and split-second timing to swap places with something that could easily be mistaken for the Ninja.
 * Shadow Ring's black outfit is based on Japanese stagehands called Kuroko (黒子).