ToME: the Tales of Maj'Eyal

hey, im still new to this game and i've been messing with charms and usable items, so there is this item called '' Rod of Annulement '' and i dont know if its classified as a charm or not but when i use other charms it doesnt go on cooldown, also it says it uses 100% of a turn but it seems instant to me like enemies dont react even without any speed buffs on me.
if any could explain how these things work i'd appreciate it

Certain Artifact level "Charms" have a separate cooldown, so they aren't affected by others.
Unsure about the other questions.