The Assassin is seen as a useful class to have on the field, but also one to be fear should you face one. When they promote from a ninja they gain weapon proficiency in bows. Despite a character losing the ability to steal when they promote from a ninja, they gain the ability to be a formidable combat class. With an Occult skill, the Assassin will perform a special critical hit, in which they will defeat an enemy in a single attack, regardless of health and defense. This skill is known as Assassinate, an assassin's critical hit has a 50% chance of being a lethality critical hit. This can even be used on the most powerful of enemies. Also when an assassin activates Assassinate, the experience they gain from killing the enemy is double the experience they would of earned if they had killed the enemy through other methods. Assassins also gain a 25% boost to Critical hit chance.
It's important to keep in mind that Assassin and the Ninja are different classes in combat. The fragile ninja loses much of its weakness once promoted. Although their defense and health is moderate at best, it's rare for an assassin to fail to evade an attack (unless the difference in level/weapon triangle takes too great of an effect). Capping their stats out at a disappointingly low strength, it's not unheard of to strike for zero damage on the more heavily armored foes. Be aware of the accurate attacks of Mages, as they'll be able to take advantage of your high speed, yet moderate resistance. However, a well trained assassin can be an extremely effective killing machine and can take out an entire army with a killing edge.
Being the promoted version of the Ninja, the Assassin can not be promoted any further.