C1: Named Juvenile Casebook

For 5s after Shikanoin Heizou takes the field, his Normal Attack SPD is increased by 15%. He also gains 1 Declension stack for Heartstopper Strike. This effect can be triggered once every 10s.

C2: Investigative Collection

The pull effect of the Arresting Windtunnel created by Windmuster Kick is enhanced, and its duration is increased to 1s.

C3: Esoteric Puzzle Book

Increases the Level of Heartstopper Strike by 3.

C4: Tome of Lies

The first Windmuster Iris explosion in each Windmuster Kick will regenerate 9 Elemental Energy for Shikanoin Heizou. Every subsequent explosion in that Windmuster Kick will each regenerate an additional 1.5 Energy for Heizou.
One Windmuster Kick can regenerate a total of 13.5 Energy for Heizou in this manner.

C5: Secret Archive

Increases the Level of Windmuster Kick by 3.

C6: Curious Casefiles

Each Declension stack will increase the CRIT Rate of the Heartstopper Strike unleashed by 4%. When Heizou possesses Conviction, this Heartstopper Strike's CRIT DMG is increased by 32%.