Devoted is an Inventionperk that has a chance each hit of replicating the Devotion ability for 3 seconds. This effect does not put the ability itself on cooldown. Devoted has a effective level requirement of 74 as the materials required can only be unlocked at that level.
Devoted will play the same animation as Devotion whenever it activates, but will not be indicated in the buffs/debuffs interface.
The devoted effect will apply after the hit occurs, so this perk is less useful at places where you are only occasionally getting hit (e.g. bosses that attack slowly).