Make it so that in addition to equipping characters with head equipment, body equipment, etc. you can equip characters with pantsu. The particularity of pantsu equipments is that contrarily to other equipment types, characters cannot share each other's pantsus (once a character wears a pantsu, the pantsu's get renamed "character's pantsu" and other character refuse to wear it). You would have the blue striped pantsu: an energetic look that grants +6 agility +1 strength, the bear print pantsu: an air of innocence that grants +6 magical resistance, etc. Pantsus should have important effects so that assigning a pantsu to a character would be an important choice. Also it would be a fun way for the player to characterize his characters in a way that doesn't require too much new assets (because it would be hidden under the clothes (unless it wouldn't?!)).
Some nuances that could be added in this system:
-Some characters could have the "pervert" trait, which make them able to wear pantsus that have been worn by other characters (the pantsu hereby changing owner).
-Characters could have the possibility to "go nopan" and get some sort of bonus (like +5 charisma or the possibility to use two items per turn or something)
-Maybe in underwater battles, characters would have to wear swimsuits instead of pantsus (but swimsuits could also be worn above water as pantsus?)