An old “friend” to Edmond Dantes, Mercain is an elite computer hacker who also keeps tabs on Amigo’s group of Assassins. He hardly ever comes out of his office, though he enjoys throwing darts. He is at home only when surrounded by technology, and although he stays with Edmond out of interest, he becomes easily agitated when his beloved hobbies are continually ostracized by the Count.
In chapter nine, Mercain went to Edmond’s house in order to gather information about Q, but instead of gaining any ground, went crazy being in an open place, and announced his plans to kill Edmond. This indicated Mercain has a problem with Agoraphobia.