Proficient; well advanced in an art, occupation or branch of knowledge.
It had started in his childhood as a focus for his attention deficit hyperactivity disorder and his love for Dungeons And Dragons had been born. Now, in his mid-thirties he was a Dungeon Master and sometimes player at the local board games club but he also travelled to events, conventions and D&D weekends to Master there.
He knew all the rules by heart, could add up the dice rolls faster then anyone and was great at reading out the adventures and describing the battles. He was proficient at the hobby but to him D&D was more then that, it was the way of his life.