WN/Testarossa

"You all already understand right? When you pass this line, your lives will forfeit. People who don’t have the resolution mustn’t pass it. Well then, have a good day."

- Testarossa warning the invading Imperial army

"Killer Lord" Testarossa ["" テスタロッサ, "Kirā Rōdo" Tesutarossa] was an Arch Demon who had evolved into a Demon Duke after she was named by Rimuru. Before the Tenma Great War, she was awakened as a True Demon Lord and evolved into a Demon King.

She is one of the ten Demons personally selected by Diablo, who had summoned various potential candidates to form the members of the Black Corps, an elite demon unit with the lowest number of troops, but with the strongest war force in all of Tempest.

She has been appointed as Diablo's right hand and is dispatched to Gobuta's corps Goblin Riders as an intelligence officer.

Appearance
Female type demon with scarlet hair. Even as an Arch Demon, she is perceived as a special individual in Rimuru's eye and possessed a dignified presence.

In the Light Novel, she has silver/blanc hair with red eyes. A beauty.

Personality
She is haughty but cold and calculating. Unlike her two colleagues, she tries to ascertain what would be the correct action under which circumstances. Vicious, but cautious. Diablo has trouble dealing with her because of her intelligence at times.

Background
She is the Demon from Lake Shore Dyed in Scarlet incident that a few years ago destroyed a small country. It was a vassal state in the Eastern Empire. The state was adjacent to a beautiful lake. The vassal state revolted against the empire and shouted for independence at that time.

The reason why their king suddenly declared his country's independence was because a noble from the Empire desired the king's only daughter, the princess. Because of that king took a drastic measure, since the state was inferior in war power to win against the Empire they tried to accomplish that through a Taboo secret art of Demon Summoning

The king gave an order to summon a powerful demon that will obey his command as the king wished and the Imperial Court Magician obeyed the order. He summoned an Arch Demon (Now known as Testarossa) but when she appeared from the Demon Summoning she destroyed the small country because she desired the kingdom's princess.

The Imperial Court Magician, whose mind was broken the instant he saw the demon, presented the princess in response to the demon's demand and she sprouted a wicked smile, as she possessed the princess's body.

The empire feared she would become a second Guy Crimson, so they dispatched the intelligence corps to deal with her.

She was killed by the intelligence corps.

Tenma Great War Arc
After the start of the war, Rimuru took her, Diablo, Carrera, and Ultima to help Milim when she lost control. Diablo and Carrera went off to do their thing after noticing how weak the four members of Apostles of the End were. Ultima chose Aria and Oruca and so Priscilla and Toruneoto were left up to Testarossa. With no care to who she fought she easily dealt with both of her opponents. Toruneoto was split in half with his Lightning Bomber being thrown back at with and disintegrating to dust. Priscilla on seeing this gave up and asked for mercy. Being in a really good mood Testarossa let her go and allowed her to live in exchange for her Angel powers and her fear. She didn't care what happened to Priscilla, she simply didn't want to dirty her hands and to provide the power of a Seraphim to Rimuru. Upon receiving her Angel Powers she was able to materialize a Death Whip.

Relationships
Testarossa, like all of those in service to Rimuru, has an undying loyalty to her Lord. While it is normal for demons to be competitive with one another via displays of their power, she views Diablo's position and power as a goal to achieve and holds a healthy respect for him. She views her fellow Demon Kings as rivals.

Magic

 * Death Streak (Blessing of Death): Summon a black flame. The flame's black light (that can pass through most substances and barrier magic) that touches a living being will rewrite its genetic code. In 99.9999% of the cases, the living being dies. The ones who survive will get its body changed into a monster and he will get a long life. Legend says that only someone who has the ability to storage his soul or spiritual life forms can withstand this magic. It's also possible for someone who can revive from complete destruction of his or her physical body.

Ultimate Skill

 * Hell King Belial:

Daily Skills

 * Magic Perception:

Battles
{{Scroll box|1====Empire’s Invasion Arc===
 * Testarossa & First Corps vs Eastern Empire's Armored Corps Tanks: Win

Clash of Dragons and Demons Arc

 * Testarossa vs Gladim: Win

Tenma Great War Arc

 * Testarossa vs Tolneod & Priscilla: Win}}

Trivia

 * She was named after the Ferrari Testarossa car.