Debuts in the Inscription of Labyrinth patch.
· Rank: A-Rank
· Class: Tank
· Element: Physical (20%) Dark (80%)
Information
Originally a subject of a Daedalus corporation experiment, she was retrieved during a mission conducted by Kurono. Later, she was transferred to Babylonia's Task Force with Vera. She is gloomy and seemingly expresionless in appearance. However, she becomes exceptionally vicious and dangerous under extreme circumstances.
Specialty
Burst — A signature move that can deal massive DMG Forced Evasion — Can remove abnormal status effects when in Haywire status
A list of recommended builds for No.21: XXI can be found here. Each tab represents one build — click the tabs below to view each one. See here for more information about Ultima Awakening and resonance slots.
Only use this set if there is already someone carrying Bathlon on the team, such as Watanabe: Astral or Kamui: Tenebrion and you don't plan to field her often.
Weapon Resonance ◇ No.21: XXI
Recommended 6★ weapon resonances for No.21: XXI can be found here listed in order of priority.
1. Tenebrion Shock
Inflicts Dark Wave effect upon dealing Dark damage. Dark Wave: reduces the target's Dark resistance by 8% for 8s. Repeated triggering refreshes the duration.
2. Dead Line Timing
Gain 2 extra random signal orbs upon deployment, and 3 signal orbs of the same color every 45s (also gain signal orbs on standby).
3. Resonant Echo
The duration of effect inflicted by Tank class skill increases to 8s.
4. Boudary's Annihilation
On QTE, shields the Construct in control for 10% of the skill user's max HP for 5s.
Priority
HIGH:
Tenebrion Shock
MEDIUM:
Dead Line Timing
Resonant Echo
LOW:
Boudary's Annihilation
Notes
Minimum recommended amount: 1
Boudary's Annihilation is mainly equipped in Phantom Pain Cage to keep 100% HP for the highest possible score.
Skills & Passives
Red Orb
Nightfall Realm
Automatically uses a 3-Ping version of this attack upon switch-in. Leaps into the air and expands a Duskglow Realm on the target's location for 1.5/3.5/6s. It pulls enemies in a large area once and then continues pulling the enemies within the realm, dealing 100%/200%/300% Physical DMG. Deals Dark DMG instead upon a 3-Ping, and No.21: XXI will stay in the air briefly, during which an Instant Dodge will release 3 Twilight Matrices on the target's location. Co-Bot: When No.21: XXI releases a Twilight Matrix, it triggers a realm collapse in the Duskglow Realm, pulling enemies in a large area and dealing 60% Dark DMG.
Yellow Orb
Dusk Bladewheel
Leaps in the direction of the joystick and releases a Dusk Bladewheel that deals a total of 140% / 280% / 420% Physical DMG. Deals Dark DMG instead upon a 3-Ping, and No.21: XXI will stay in the air briefly, during which an Instant Dodge will release 3 Twilight Matrices on the target's location.
Blue Orb
Cluster Recursion
Enters the Hyperposition state and copies the following 1/2/4 Basic and Shadow Prism Attacks. The effect does not stack. Co-Bot: Launches a dash attack at the current target, dealing Physical DMG equal to 40% of No.21: XXI's ATK and reducing the DMG target deals by 20% for 5s. It can only be triggered once every 2s
Basic Attack
Prism Barrage
Basic Attack: Attacks with laser beams to deal a total of 348% Physical DMG. Co-Bot: Automatically attacks the current target, dealing Physical DMG equal to 20% of No.21: XXI's ATK per hit. The Co-Bot always stays on the field.
Signature
Shadow Prism Collapse
Signature Move: No. 21: XXI: Consumes 120 Energy to expand an Enhanced Duskglow Realm on the target's location and enters Quick Attack mode. Spends all Signal Orbs and Shadow Prism Energy for 3s of unlimited Blue Orbs and extreme attack speed. Each Basic Attack deals 20% Dark DMG. When Quick Attack mode ends, the realm explodes to deal 600% Dark DMG and empty No.21: XXI's Energy, Blue Orbs, and buffs. While performing the Signature Move, creating 1/2/3/4/5 Twilight Matrices will increase the explosion DMG by 40%/80%/120%/160%/200%. When there are 6 Twilight Matrices, the Signature Move will achieve an S Rank, increasing the explosion DMG by 300%. Co-Bot: It will not perform other skills while the Signature Move is being used. When Quick Attack mode ends, it releases a Force Wave to detonate all Twilight Matrices.
QTE
Twilight Shackles
QTE: Expands a Duskglow Realm on the target's location to deal 200% Dark DMG, creates 3 Twilight Matrices, and triggers a realm collapse.
Class
Tank
Attacks lower the target's Extra DMG Reduction by 20% for 5 seconds.
Awakening
Ultima Awaken
Gains 3 Signal Orbs when entering battle.
Core
Shadow Prism Agglomerate
Core Passive: No.21: XXI's Basic Attack will create 1 Shadow Prism Energy. Upon reaching 4 Shadow Prism Energy, the next Basic Attack will empty all Shadow Prism Energy to perform a Shadow Prism Attack and create 1 Twilight Matrix on the target's location for 3s that deals 20% Dark DMG and grants No.21: XXI 2 Signature Move Energy and 50 Dodge Energy. When the Co-Bot's Force Wave destroys a Twilight Matrix, it will trigger a Resonance Pulse, dealing 50% Dark DMG to nearby enemies. Instant Dodge: When No.21: XXI is in Haywire status (when attacked, downed, or in mid-air), press the Dodge button and spend 1.2x Dodge Energy (300) to perform Instant Dodge to negate all uncontrollable states and create 1 Twilight Matrix on the target's location. Instant Dodge grants No.21: XXI Super Armor for 2s and a shield equal to 15% of max HP.
Leader
Faded Camouflage
Dodge Gauge limit and Extra DMG Bonus of team members increase by 250 and 5%.
SS-Rank
"Phobia"
Passive: When No.21: XXI has a shield, Extra DMG Bonus increases by 5%. If not, Extra DMG Reduction increases by 10%. A Blue 3-Ping will fully restore Shadow Prism Energy (inactive when performing her Signature Move).
SSS-Rank
"Jubilance"
Passive: When creating a Twilight Matrix, grants allies on the field 20% Extra DMG Reduction and 25% Extra Dodge Gauge Recovery Speed for 2s. It can stack up to 3 times. Duration will not reset when it is re-triggered. Enemies in the Duskglow Realm will be afflicted with Chain Fusion (Dark Resistance decreased by 10%) for 5s.
SSS+ Rank
"Melancholy"
Passive: When her Signature Move achieves an S rank, further increases the DMG of the explosion from Duskglow Realm by 210% The Co-Bot's attacks will grant allies on the field a shield equal to 2% (stack up to 10%) of No.21: XXI's max HP.
Physical (20%) 
Dark (80%)
