This is just a temporary topic addressing what items will do once we introduce the HP system.

Items that add Defense will reduce damage taken by a flat value. Items that add Attack will increase your damage by a flat value.

Type-specific items act as above. Silks increase defense, Dusts increase attack and Gems increase both. These items are only usable if your character has the right type!

Type-boosting items will increase damage from attacks of that type.

This is, obviously, very temporary and full details will be revealed when the HP system is rolled out. Note that these effects are for chapters.