All mercs use rank 2 spells. There is no way to upgrade them. (I use J5 mercs. I wouldn't know if lesser mercs use Rk1 spells, but none use 3).
Poster got their answer in yesterday's post but good info on which ones they use. https://forums.daybreakgames.com/eq...-rank-3-mercenary-spells.275888/#post-4038538
