The Whale Fountain must first be activated by using eight Celestial Tokens. Once activated, Serendipity allows the player to collect and spend Celestial Fragments to carry over items from one reincarnation to the next.
Additionally, the fountains offer two options when interacting with them. First, the player can pray for life to spend 200 Celestial Fragments and obtain a Celestial Essence item which upon dying, Serendipity will revive the player. Second, the player can pray for time by spending 100 Celestial Fragments to gain an additional day for that reincarnation. The costs increase upon subsequent uses.