Ein Abgrund

Ein Abgrund is a former assassin of Rebellion, who is currently working with Or-Gaule. She is also the sister of Yui Tatara and a member of the Abgrund Family.

Appearance
Ein has long black hair and is shown wearing a black dress. She also wears a black glove over her torn right arm.

Personality
Ein is a cold-hearted woman. She loves many kinds of flowers, especially roses that bloom by sucking blood from people. She loved such beauty that can be created from human lives and joined Rebellion for this reason.

History
At some point, Ein joined Rebellion, as she believed they would help her in achieving new levels of beauty. However, she was disappointed in Rebellion, leading her to side with Or-Gaule.

She is also part of the famous family of assassins, called Abgrund. She murdered the entire family, except for Yui, who was away in Japan, participating in the Seven Stars Sword Art Festival.

Night of Massacre
Ein, Big Baby and Naseem Al-Salem, lead by Or-Gaule, destroy the Rebellion headquarters and kill 8 of Rebellion's apostles, including Wallenstein. They are unable to find Tyrant, whose location is unknown. They then head for Cradleland, which Or-Gaule takes control of.

Kardia Urban Warfare
Ein later appears in Vermillion, in the imperial family's castle Flareverg. Ein attacks the guards and then engages Sirius Vermillion. Sirius though is unable to hit Ein and is almost killed, but he is saved when Yui Tatara appears. She has been masquerading as a maid in Vermillion. Yui reveals that Ein killed their family and that she is here for revenge. Yui and Ein then are about to begin their battle, but are most likely stopped, by Lunaeyes' declaration, that the tournament between Vermillion and Cradleland will be held.

Responsibilities as a Royalty
After the announcement, Ein is ordered by Or-Gaule, who has agreed to the tournament, to withdraw from Vermillion. Ein does this. Yui questions if Ein is running away, but Ein simply says that Yui should chase after her if she thinks she can win. Yui though lets her older sister go.

Ein, along with Or-Gaule, Naseem, Big Baby and Johann, is chosen as one of the representatives of Cradleland, for the upcoming tournament.

Imperial War Outbreak
On the day of the tournament, both Team Cradleland and Team Vermillion meet in the capital of Cradleland, Lucier, which will serve as the battlefield for the tournament. As the tournament begins, Naseem creates a giant sandstorm, that blows the other participants high into the air. Ein survives the fall and moves to the rose garden of the royal castle. There she is confronted by her sister, Yui.

The Unturning Assassin
The battle between the sisters quickly begins, with Yui charging towards Ein. Ein, however, utilizes her multiple Noble Arts to fend off Yui, who is forced to go on the defensive, using her Total Reflect to block all of Ein's attacks. Ein continues to assault Yui with her plants, until she finally manages to overpower Yui's ability and grab her with vines. Ein then thrusts one of the vines into Yui's throat, brutally choking and damaging her. As Yui is extremely injured, Ein tells her that if she gives up, she will let her go and continue her life as an assassin, However, instead of giving up Yui uses another Noble Art, Damage Reflection, to transfer the damage she has received to Ein, causing Ein to receive all of Yui's brutal injuries.

Ein though continues the battle, activating her trump card, Yggdrasil Abyss, that causes a tree to grow out of her and summon multiple deadly beasts from the tree's bulbs. Yui is overwhelmed by these beasts and Ein's other attacks, with Ein continually taunting her.

Abilities
Master Assassin: As a former member of the Abgrund Family, Ein has most likely been trained from childhood to become a deadly assassin. She was able to infiltrate into the capital of Vermillion, Flareverg.

Great Speed: Ein is extremely fast, as she was able to effortlessly dodge Sirius' attacks.

Plant Control: Ein's ability as a Blazer is to control different kinds of plant life. She possesses an absolute mastery of the ability, being able to create plants of highly differing qualities, that all are highly dangerous. She is also able to create these plants from her body.
 * Beast Creation: By contaminating the surrounding soil with her own magic, Ein is capable of creating multiple dangerous beasts from the surrounding vegetation. These beasts formed from plants, follow her commands without hesitation or fear, making them very dangerous. She utilizes this ability with her Noble Phantasm, Yggdrasil Abyss.

Device
Astarotte: Ein's Device takes the form of a seed, that is embedded in her womb. This seed is able to breed different kinds of plants.
 * Sleeping Beauty: Ein creates poisonous flowers, that can paralyze the opponent with their gasses. These gasses would be able to even paralyze an elephant with a single inhale.
 * Rose Whip: Ein creates a vine whip from her left hand. This whip is extremely fast, as if it had a mind of it's own.
 * Bloody Mary (lit. "Bloodsucking Queen"): Ein creates a seed, which she then throws on her opponent. This seed then plants itself in the opponent, and sprouts vines which tear the opponents flesh from the inside.
 * Trigger Happy (lit: "Chattering Tulips"): Ein creates multiple tulips from the ground, that release high-pitched screams and shoot bullet seeds at the opponent, like bullets from a machine gun.
 * Bamboo Javelin (lit. "Piercing Bamboo"): Ein creates spears of bamboo from the ground, that then attack or trap the opponent.
 * Crunching Alligator (lit. "Glutton Venus Flytrap"): Ein creates a giant version of a Venus Flytrap, a carnivorous plant. The man-eating plant is big enough to swallow a person and strongly like an alligator.
 * Yggdrasil Abyss (lit. "Dark World Tree"): Once Ein's Device consumes all her mana, her body begins to sprout a tree, that grows 50 meters high, tearing her body. The tree turns the surrounding vegetation into twisted beasts by directing Ein's magic into the soil with its roots. The tree itself can also be used for attacking.

Trivia

 * "Ein" means "one" in German.