Book of Insight

The Book of Insight is accessible between campaign missions. In it you can spend Insight to gain new abilities, unlock new pieces and improve the Citadel. Purchased skills can be refunded at any point.

Citadel

Citadel skills improve the citadel.

Skill	Effect	Type	Expedition Level
Perla Escape	Iris automatically teleports to the Citadel when her health is low	Passive	I
Headquarters Defense	Generates a field of damage that hurts all Horrors near the Citadel	Active	I
Reinforced Stonework	Citadel gains +250 health	Passive	II
Mistleap	Teleports all units in the arte's field to the Citadel	Active	III

Units

Units skills improve the attacks of one the units.

Skill	Effect	Expedition Level
Bowman: Menelaus Shot	Bowman attacks 3 horrors at once.	I
Lobber: Powder Ball	Lobber attacks hit a larger area	I
Captor: Pearl Web	Captor attacks stun horrors	II
Cannoneer: Volatile Cannonball	Cannoneer attacks hit a larger area	II
Ballista: Cluster Bomb	Ballista attacks hit a larger area	III
Hunter: Execution	Hunter attacks instantly kill low-health enemies	III

Pieces

Pieces skills unlock new pieces.

Skill	Unlocked pieces	Expedition Level
Advanced Stone Pieces	Stone Rampart, Stone Arches and 1x3 Stone Brick Mounted Fire Arrows, Mounted Poison, Mounted Hell Arrows and Mounted Hell Poison specialist boosts	I
Advanced Wood Pieces I	Wood Scaffold and 1x3 Stone Strut Mounted Banner and Grand Mounted Banner general boosts	II
Advanced Wood Pieces II	Claw Trap	III

Iris

Iris skills improve Iris' capabilities and unlike other skills they come in mutually-exclusive groups of two as well as two levels each.

Skill	Effect	Type	Expedition Level
Perla Attack	Iris gains a basic attack	Passive	I
Arte: Palido Darts I	Iris' attack strikes up to 4 horrors and deals 6 more damage Mutually exclusive with Arte: Palido Impact	Passive	I
Arte: Palido Impact I	Iris' attack deals 12 more damage Mutually exclusive with Arte: Palido Darts	Passive	I
Arte: Sunderbolt I	Deals damage in one attack in a large area Mutually exclusive with Arte: Tempest	Active	I
Arte: Tempest I	Deals damage in multiple attacks in a large area Mutually exclusive with Arte: Sunderbolt	Active	I
Leather Undershirt	Increases Iris' health	Passive	II
Arte: Healing Veil I	Reduces damage to buildings and restores health to buildings Mutually exclusive with Arte: Pounding Veil	Active	II
Arte: Pounding Veil I	Slightly reduces damage to buildings and damages horrors in the area Mutually exclusive with Arte: Healing Veil	Active	II
Chainmail Undershirt	Increases Iris' health	Passive	III