Ninety Nine Nights - Use your blue special move if you have it. Otherwise just kill every enemy and ignore the troll until you kill everything else. There is a sword in a chest in this area but you cannot wear it until you are level three. Now carefully kill the troll (block a lot) and the mission will be finished. You might want to go through this level again at some point if you didn't get an S rank on this level. It is also worth it to go through levels with an S rank and get an A rank since those items are useful as well.