Warlock
Warlocks (a subclass of the Mage) are one of the most powerful damage dealers, and the top area nukers in the game. However, getting caught by surprise or getting too close can turn them in the easiest to kill class. Able to cast effective combat control spells, drain life and mana, deal fast elemental or physical damage, cause damage over time, and use many of the strongest curses, makes warlocks the most dangerous part of any army. Sadly, along with poor defensive skills, it makes it one of the most targeted classes too. But also this can be used as an advantage by experienced players.