The Masqueraider switches between roles using a clever mask system. While the first couple of skills in any line are available no matter what mask is worn, all of the other skills are mask-dependent. The masks range from coward (which relies on heals, escapes, and ranged DPS) to classic (which allows for excellent melee combat and helpful auras). There's even a Psychopath mask, which gives you a shortcut to the game's forums so that you can quickly write rants. Just kidding -- it's all about fire DPS.
The Masqueraider was part of WAKFU's February 26th update, which also included AP set rebalancing and profession bags.