What charecter from greek mythology can be described as being vain?

A multitude, but the personification of vanity was Narcissus, who was so in love with his own reflection (seen in a clam pool of water) that he refused to leave it and starved to death. The gods, in pity, turned him into a Lily that bears his name to this day.

The Narcissus Lily is better known in the States as the Daffodil.