|Spoiler Alert: This article/section contains details about future plot lines described in the light novels, not covered in the anime. Do not proceed unless you want to be spoiled.|
|Novel Debut||Date A Bullet 2|
Rook is created from an Empty host after being struck by the Scorpio Bullet <Akrab>. No matter how many times Rook dies, she can always be revived through another host using the White Queen's bullet. As one of the Three Executives of the White Queen's forces, Rook's role is to serve as a fortress and protect the Queen like a bodyguard.
Rook has long, straight white hair usually left down, with bangs that cross over the middle of her forehead. She is noted to be largely uninteresting to look at due to her extreme similarity in appearance to any other Empty. Her white-themed appearance is noted to be 'pure', and starkly contrasts against her red scythe, <Vermillion>. Her Astral Dress resembles a leotard accessorised with frills and detached sleeves that hugs her lithe frame.
Rook, like all of the White Queen’s soldiers, is a fanatical follower. She dotes on the White Queen and harbours an immense, unhealthy love and adoration for her. She has stated on multiple occasions that she would die for the White Queen, and has no qualms with carrying out whatever the White Queen orders her to do. In comparison to Pawns, the White Queen treats Rook with considerably more trust than the rest of her army, granting her the ability to act on her own accord and perform rearrangements of her castle if Rook deems it necessary to suit the White Queen’s needs, even in her absence.
When working as a double agent under Mayuka Momozono, Rook was shown to be obedient and apathetic. Like many Empty, Rook was able to act with a disconnect from the world around her, only carrying out orders from the person who employed her at the time. Rook was shown to be Machiavellian numerous times when working with Mayuka, giving her multiple ideas on how she would be able to achieve her goal of becoming Dominion. However it became apparent that Rook was manipulating Mayuka to retrieve the Voice of the Moon for the White Queen, and Rook had no issues with turning on Mayuka without a moment’s notice and was fully prepared to murder her to carry out her orders. This skill and ability to manipulate and put up a facade so effectively speaks volumes of Rook’s capabilities.
When interacting with the White Queen, Rook behaves like a loyal and capable subordinate- which she is. She is willing to lay down her life and die for the White Queen, expressing no distaste or ill feelings towards the Queen when she was killed by her. To Rook, serving the White Queen is of utmost importance and is the epitome of joy to her.
Rook also appears to have a fragile temper. She grew enraged very easily on multiple counts, once when Kurumi Tokisaki taunted and goaded her about the White Queen, and once when Mayuka mocked her fighting ability.
Powers and Abilities
Rook’s Unsigned Angel takes the form of a large scythe. It has a large variety of uses for close quarters and ranged combat. It is stated that, despite being an Unsigned Angel, Vermilion boasts incredibly high quality destructive power. As well as being able to be used as a battle scythe by swinging and slashing, Rook is able to give Vermilion commands. Each command spoken will elicit a different effect.
- Capture: Used to snatch away a certain object, and only takes away what is necessary. It was used to take the Voice of the Moon from Rinemu Kirari without harming her.
- Bend: Vermilion's handle will bend in order to be used offensively or defensively.
- Extend: Vermilion will extend for better ranged combat.
- Fly: Vermilion can be used as transportation, and is described to be akin to a jet, spewing flames as a method of propulsion. Rook uses it to flee the scene in Volume 2.
- Multiply: Vermilion can multiply into eight separate scythes. These scythes can hover in the air without Rook’s direct input.
- Attack: Usually used after multiply, the scythes will immediately assault the target.
- Sharpen, Ignite, Melt and other variations: The scythes can take on an elemental power given to them. Depending on the command, the scythes will gain traits of what they were ordered to do. Freeze, for example, will have the scythe shoot out sharp icicles towards the target.
- Guard: The scythe/scythes will respond to protect the user. By rotating around the user or effectively blocking an assault like shields.
- Search: Search will force the scythes to be on alert for attacks, and respond accordingly.
- Counter: Used to counter attacks. Vermilion can also transform into a different weapon, such as a spear, if that is most suited to counterattack. They can also transform into shields.
- Scatter: Vermilion will split into innumerable pieces, and the shrapnel will assault the enemy like a barrage of arrows.
- Combine: Vermilion will combine back into one scythe, and is used after Multiply or Scatter.
Rook is also surprisingly powerful for a Quasi Spirit. She was able to keep up in speed with Kurumi Tokisaki after she used Aleph to accelerate time on herself. Rook also has battle prowess, able to move with fluidity and skill in order to take controlled amounts of damage when being assaulted.
As one of the Three Executives, Rook can be continuously revived through the Scorpio Bullet being used on new Empty Quasi-Spirit hosts. However, consecutive revivals within a short span of time can lead to Rook being momentarily paralyzed for a few minutes after being resurrected.
- (To Mayuka Momozono) “In order to replenish my reiryoku, I'm going to gouge out your Sephira fragment now.” 
- (To White Queen) “Yes, I offer everything I have to you my dear Queen.” 
- (Directed to White Queen) “How sad! How sad! How sad! The taste of betrayal is so bitter...! The love that I can never get back is too sad! So, at least I have to kill them to prove my loyalty!”