Fountain of Youth

Fountain of Youth is a sacred treasure that grants anyone eternal life. It was guarded by Elaine for seven hundred years before Ban drank it and gained his immortality.

Background
The creation of the fountain is unknown, but it is believed that a lick will grant you ten years of extra life, a swallow will add a hundred years to your life, and drinking it all will grant you eternal life. The fountain was guarded by Elaine alone for over seven hundred years, waiting for her brother, King, to come back. If the fountain was drink all of it, the Fairy King's Forest will die out.

Side Story 1
Ban travels to Fairy King Forest in order to drink the Fountain of Youth, to live forever. However, he encounters its Guardian Saint, Elaine who keeps on preventing him from doing so. Ban gives up when Elaine explains the importance of the fountain, and after she realizes that Ban truly desires to give up, she lets him go. They bond with each other over a span of seven days, until an Unknown Demon suddenly comes and burns down the forest. Ban attempts to kill it and successfully rips one of its heart out, but to his surprise, it had more than one heart. Quickly, the monster deals fatal wounds onto Ban and Elaine. In order to survive, Ban persuades Elaine to drink the fountain, only to discover her kissing him and delivering the liquid directly mouth to mouth. Ban immediately recovers from his injuries and eliminates the Unknown Demon easily.