Elise

Literal Goddess.
* She has an HP shave skill that deals damage based on the enemy's HP. This is amazing against bosses. (Alliance Bosses are excluded.) 
* Even without the hp shave skill, her damage is great. She can pick off front-line units with ease. However, this is only possible at higher upgrades.
*One of her cons is that as an Adventurer, she has only 10% crit rate and not the 20% of mages. But she makes up for this with her ASPD.
*Against the Yellow Cube Boss, because of the natural self-knockback attached to her main skill, she actually can't be damaged as she knocks herself out of its range before the boss can attack her. So, she's great at damaging and delaying the yellow cube boss from reaching your rear.
*Check Natrix to see how she can be used against it.