Se: d’Artagnan is highly impulsive. His life is nearly cut short dozens of times because he rushes into dangerous situations. This is shown from the very beginning when he challenged three Musketeers to the death on the same day. On the bright side, he is always ready to jump into action, and his skills usually back up this desire.
Fi: d’Artagnan is entirely motivated by his emotions. He is quite willing to drop everything whenever he sees a mysterious man from his past. He takes his word as a gentleman very seriously. If a woman he loves tells him to sacrifice something he wants (such as revenge) he will do it without second guessing. In this way, he is a lot like a classical knight.
Te: d’Artagnan quickly devises a plan to take revenge on Milady. It was a cruel, but effective plan, and only fell apart when he told her the truth, without really considering the consequences.
Ni: Even though he is constantly distracted, d’Artagnan does have long term goals that he tries to accomplish. Examples of this include getting revenge, becoming a musketeer, and saving his lost love.