Should i consider martial arts if i want to gain more muscle mass?

Not necessarily: Any sport to do with continuous hard exercise to the muscles (weight lifting) and the right food and supplement could provide the tool to gain muscle mass.

Yes and no: There is no doubt that martial arts will increase your strength, flexibility and balance, however you are not likely to "bulk up" like if you were a wt lifter/body builder. It depends on what you are going after. A martial artist's body is strong, but not huge like a body builder's. This is because speed and cardio tend to decrease if you are really muscle heavy!