Type	Icon	Name	SP	Required	Description 【Switch】
B		An Open Book	300	—	Enables【Canto (Rem.; Min １)】. At start of player phase or enemy phase, inflicts【Exposure】,【Discord】, and【Stall】 on foes with Res < unit's Res and that are within 2 spaces of another foe through their next actions. At start of combat, if unit's HP ≥ 25%, inflicts Atk/Res-5 on foe, foe cannot make a follow-up attack, inflicts Special cooldown charge -1 on foe per attack (only highest value applied; does not stack), deals damage = 20% of unit's Res (excluding area-of-effect Specials), reduces damage from foe's attacks by 20% of unit's Res (excluding area-of-effect Specials), and grants Special cooldown count-1 to unit before unit's first attack during combat.	Enables【Canto (Rem.; Min １)】. At start of player phase or enemy phase, inflicts【Exposure】,【Discord】, and【Stall】 on foes with Res < unit's Res and that are within 2 spaces of another foe through their next actions. At start of combat, if unit's HP ≥ 25%, inflicts Atk/Res-5 on foe, foe cannot make a follow-up attack, inflicts Special cooldown charge -1 on foe per attack (only highest value applied; does not stack), deals damage = 20% of unit's Res (excluding area-of-effect Specials), reduces damage from foe's attacks by 20% of unit's Res (excluding area-of-effect Specials), and grants Special cooldown count-1 to unit before unit's first attack during combat. 【Canto (Rem.; Min １)】 After an attack, Assist skill, or structure destruction, unit can move spaces = any movement not already used that turn (min. １; if unit used a movement skill that warped them, unit can move １ space(s)). (Once per turn. Only highest value applied. Does not stack.) 【Exposure】 Foe's attacks deal +10 damage. 【Discord】 Inflicts Atk/Spd/Def/Res-X on unit during combat (X = 2 + number of allies within 2 spaces of unit; max 5). 【Stall】 If unit has "unit can move 1 extra space," converts that effect into "restricts movement to 1 space."
This skill can only be equipped by its original unit.

* Unused restrictions: No restrictions.

Effects

Effects	Targets	Conditions
Status effects
Exposure	Foes within 2 spaces of other  Foes	At start of Both Phases if  Foe's Res <  Unit's Res
Discord
Stall
Map effects
【Canto (Rem.; Min １)】	Unit	—
Combat effects
Atk/Res-5	Foe	Unit's HP ≥ 25% at start of combat
Cannot follow-up
Special cooldown charge -1
Boosts damage by X% X = 20% of  Unit's Res	Unit
Reduces damage by X% X = 20% of  Unit's Res from  Foe's attacks
Special cooldown count-1 before  Unit's first attack

Notes

• If an effect that grants "another action" to unit would trigger, (such as with  Galeforce) the extra action will be granted before 【Canto (Rem.; Min １)】 triggers (excluding effects that grant "another action" after Canto).
  • 【Canto (Rem.; Min １)】 will not trigger after an effect that grants "another action" if it has already been triggered that turn or if the unit does not perform an action.
  • 【Canto (Rem.; Min １)】 triggers after "after combat" movement effects such as  Repel 4,  Harrowing Call, or Movement Passives.
  • If 【Canto (Rem.; Min １)】 has already been triggered that turn, Canto re-enabling effects can allow 【Canto (Rem.; Min １)】 to trigger again.
  • If an ally has an effect such as  Demonic Tome,  Salvage, or  Summer Chilling; the unit can also warp to the ally after triggering Canto regardless of distance restrictions.
•  Canto Control will reduce the amount of movement granted by 【Canto (Rem.; Min １)】 to 1 space (or 2 spaces with  Salvage) for Range = 1 units and 0 spaces (or 1 space with  Salvage) for Range = 2 units.
• 【Canto (Rem.; Min １)】 takes into account the unit's Move Type and the movement restrictions involved with it. For Example, a  Cavalry unit cannot use 【Canto (Rem.; Min １)】 to enter or cross through a forest.
  • 【Canto (Rem.; Min １)】 also takes into account effects that alter a unit's normal movement such as movement preventing effects, Divine Vein effects, Pass effects,  True Charge,  Traverse Terrain, and 【Pathfinder】.
  • 【Canto (Rem.; Min １)】 also takes into account warping effects such as  Guidance 4 and  Air Orders. However, the distance is limited to the maximum amount of spaces allotted by 【Canto (Rem.; Min １)】.
  • 【Canto (Rem.; Min １)】 also takes into account status effects that alter a unit's movement value such as  Mobility increased,  Gallop,  Stall, and  Gravity.
    • 【Canto (Rem.; Min １)】 will have the remaining value be reduced to 1 if the unit was inflicted with  Stall or  Gravity and did not move.
    • The remaining value for 【Canto (Rem.; Min １)】 will not be affected if the unit was inflicted with  Stall or  Gravity after combat.
• An Open Book applies the  Exposure status effect.
  • Any 【Penalty】 effect on a unit lasts until that unit takes an action. If the unit takes multiple actions in a turn, they will only have  Exposure for their first action.

• The damage boosting effect is a flat +10 damage that ignores the foe's Def or Res when calculating the damage boost, and can be reduced by damage reduction effects such as  Archrival,  A/S Rival Break, and  Dodge.
  • Damage boosting effects stack additively, similar to flat damage-reduction effects and interactions related to the weapon-triangle, such as  Triangle Adept and the weapon-triangle advantage boost.
  • A foe equipped with Invincibility Seals will neutralize all sources of damage except from Røkkr area-of-effect Specials and the minimum 1 damage from Umbra Burst weapons.
  • A foe using attack damage preventing effects can neutralize damage dealt from the foe's own attacks and the unit's attacks (Units with Umbra Burst weapons will take and deal the minimum 1 damage).
  • For more information, see Damage calculation.
• An Open Book applies the  Discord status effect.
  • Any 【Penalty】 effect on a unit lasts until that unit takes an action. If the unit takes multiple actions in a turn, they will only have  Discord for their first action.
  • The stat reduction that can be applied during combat by  Discord is considered a temporary debuff.
• An Open Book applies the  Stall status effect.
  • Any 【Penalty】 effect on a unit lasts until that unit takes an action. If the unit takes multiple actions in a turn, they will only have  Stall for their first action.
  •  Stall does not convert  Mobility increased into  Gravity, it restricts the movement of units with  Mobility increased to 1 space.
    •  Fetters of Dromi will neutralize the movement restriction of  Stall, but  Mobility increased will be removed from it's user.
    • Since units inflicted with  Stall will still have  Mobility increased, effects that require a 【Bonus】 effect or Mobility increased to trigger such as  Atk Liberate or  Empathy will still trigger.
    • If the affected unit does not have  Mobility increased,  Stall has no effect, but can still be used to trigger effects that require a 【Penalty】 effect such as  Spd Shackle or  Paranoia.
• The stat reduction that can be applied during combat by An Open Book is considered a temporary debuff.
• An Open Book can prevent the foe from making a standard follow-up attack.
  • As a general rule, if a unit is both prevented from making, and guaranteed to make a standard follow-up attack, the effects cancel out, and the Spd difference is used (including effects that alter the Spd difference such as  Frozen).
  • An Open Book will not prevent a unit with a "unit attacks twice" effect from performing the 2 consecutive attacks, but the the unit will not be able to perform a standard follow-up attack.
  • An Open Book will not prevent the additional follow-up attack of Potent Follow effects.
  • Effects such as  Mag. Null Follow or  Null Follow-Up will neutralize the follow-up preventing effect of An Open Book.
• The "Special cooldown charge -X" effect will stack with the "Special cooldown charge +X" effect.
  • For example, if a unit is affected by both  Guard and  Special Cooldown Charge +1, the effects will stack and the cooldown will go down without penalty or bonus.
• If used alongside another source of "Special cooldown charge -X", only the higher of the two charge reductions will apply.
  • This means that if a unit has two "Special cooldown charge -1" effects from two different sources, the battle will play out as if only one "Special cooldown charge -1" effect is active.
• Skills such as  Tempo Echo and  Arcane Þrima will neutralize effects that inflict "Special cooldown charge -X" on its user.

• The damage boosting effect of An Open Book ignores the foe's Def or Res when calculating the damage boost, and can be reduced by damage-reduction effects such as  Archrival,  A/S Rival Break, and  Dodge.
  • Damage boosting effects stack additively, similar to flat damage-reduction effects and interactions related to the weapon-triangle, such as  Triangle Adept and the weapon-triangle advantage boost.
  • A foe equipped with Invincibility Seals will neutralize all sources of damage except from Røkkr area-of-effect Specials and the minimum 1 damage from Umbra Burst weapons.
  • A foe using attack damage preventing effects can neutralize damage dealt from the foe's own attacks and the unit's attacks (Units with Umbra Burst weapons will take and deal the minimum 1 damage).
  • For more information, see Damage calculation.
• The flat damage-reduction effect is calculated after offensive Specials, damage boosting effects such as  Arcane Thorn and  Change of Fate, and "reduces damage by X%" effects such as  Archrival and  Dodge.
  • If a an effect such as  Miracle or  Roy: Of Binding's boosted Special effect can trigger, the damage-reduction effect will not trigger and the user will still survive with only 1 HP.
  • Umbra Burst weapons will always deal a minimum of 1 damage even if the foe uses attack damage preventing effects, Invincibility Seals, or damage reduction effects.
  • Flat damage-reduction effects stack additively, similar to damage boosting effects and interactions related to the weapon-triangle, such as  Triangle Adept and the weapon-triangle advantage boost.
  • Flat damage-reduction effects cannot be neutralized or reduced only during combat by effects such as  Share Spoils+ or  Halves non-Special damage reduction.
  • For more information, see Damage calculation.
• An Open Book's Special cooldown count reduction that occurs during combat is a flat -1 and is not affected by effects related to Special cooldown charge such as  Guard,  Special Cooldown Charge +1, and  Tempo Echo.
  • All flat cooldown count increases and/or reductions during combat will stack with each other if they trigger at the same time.
    • For example, if a unit has  Preempt Pulse and  Hush Spectrum, the effects will stack and the unit's cooldown count will neither increase nor decrease.

List of owners

Unit	Skill chain
Heimdallr: God of Foresight	An Open Book 5
Heimdallr: New Year's Vision	An Open Book 5

In other languages

Language	Name
Japanese	すべて読めていた
German	Ein offenes Buch
Spanish (Europe)	Un libro abierto
Spanish (Latin America)	Un libro abierto
French	Un livre ouvert
Italian	Un libro aperto
Traditional Chinese (Taiwan)	一切如我所料
Portuguese	Um livro aberto

See also

• Sabotage Passives
• Discord Passives
• Havoc Passives