since your a martial artist mate then you really want as clean a muscle gains as possible...no fat.
Imo you are looking at a few pounds a month (natural) if you train smart and eat a good quality diet with suffice calories. any more than that then you are very genetically gifted or gaining fat.
you need practical strenth so hypertrophy specific training isnt ideal imo. basic lifts (deadlift, squat, bench press, shoulder press), olympic liftts and bodyweight lifts in a full body workout 3 times a week are the way forward for you.
along with a good diet this will let you make gains in proportion to your increasing strength in a time that suits your body.
steroids aint the answer for you i dont think.