In my question I meant if it was possible to fight Legate before the finally battle; I already know to get into the camp, (armor-hopping, for all you people who know what I am talking about) and since apparently there is noway to fight him before the end of the game, I hope Bethesda Studios makes DLC to continue the game, and have it end somewhere else. After a series of main quests, though mind you, cause in Fallout 3, It was boring once you discover every location and collect every weapon and do every quest, so to have a DLC where it only prolongs the end would be fun.