It's a must, at least in Frontline.

- Auto-ability to permanently run faster than everyone, with no condition (unlike Bard).
- Melee class that can do good ranged attack, Throwing Daggers, Raiton.
- Melee class that can do magic attack, Raiton, an instant skill, as powerful as Fester and Flare, with very easy 3 steps combo (all instant abilities).
- Hide, almost impossible to defend unless you want to spam some AoE all the time.
- Can interrupt spell casting without any ability, just keep doing their super fast attacks and it's an auto-interruption.