Every character can use the skills from their currently equipped items. These skills however require spirit. And not all skills are visualised in a report- some of them need to be casted successfully, in order to be seen- e.g, a hero might attempt to use the Ambush skill- in the detailed battle report it will say you have made an attempt, but only if you deliver a critical hit will it say that you have used the skill successfully (and will take some spirit points for that).