Summary:You can obtain these gears by composing using Moonlight Box at a 100% success rate. The items required to compose them are different by parts:[Full Text:]

Summary:For every class Warrior/Summoner/Mage/Archer exists a level 42 set, the items of those level 42 sets are called Legends they are green and always have the same stats (Note: some pieces have sockets).[Full Text:]