Complex sentence: The Raiment is said to be what the people of the Moon wear in order to return to it and the potion, though its name says that gives immortality, actually boosts the life energy of a being for a period of time.
Split into simpler sentences: The Raiment is said to be what the people of the Moon wear in order to return to it. The Potion, though its name says it gives immortality, actually just boosts the life energy of a being for a period of time.