Varush is a magic samurai that plays like a bruiser. Primarily using Slash attacks that scale off of MAG while also having some SPR to deal with other mages. Since he's a MAG-based unit, he's able to also deal high magic damage or give high heals through his sub-job options.
His main job, "Bladesoul", is like an upgraded (or modernized) version of Rune Knight's job since it's also melee ranged attacks with MAG scaling, has SPR piercing rate passive, and HP draining attack. Compared to Rune Knight, Bladesoul has a better offensive buff since it lasts for 3 turns, and comes with more defensive options, mainly to go against other magic damage dealers. This tankyness will help Varush survive better so that he can recover lost HP through regen or Spirit Stealer.
His damage isn't comparable to other focused damage dealers, but his advantage is in attrition. The tankyness + damage absorption attack works well together, and he has a high chance of inflicting Paralyze through his burst. Going with White Mage sub job even lets him heal others and fully revive a unit, while going with Kotodama Wielder sub job will give him some magic attacks so that he can use 2 damage types.