Rod of Annulement and charms

[Deathgow]

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

[HousePet]

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