Is Aikido harmful to the enemy?

Aikido was designed so that both the attacker/enemy and the person defending do not get hurt during a conflict. Aikido is a way to resolve conflict as soft and peaceful as possible. Just like any art, once the student knows the art, they also have control over how much they apply a control or lock on a person. Many of the Aikido techniques can be deadly however they are not practiced that way. The level of punishment that you put upon a person is up to you once you know the technique.