Rafayel explains the Sea God succession ceremony to MC: for a creature as selfish as a human to willingly give their entire heart is the truest act of devotion, and that sacrifice seals the new Sea God's power to defend Lemuria. He asks if she wants his heart. In love with him, she consents to the ceremony. They enter the Sea God Temple together. Only Rafayel walks out. Lemuria immediately starts to collapse: Lemurians turn into monsters, the undersea sun goes dark, and the sanctuary is lost. He ages and dies without ever revealing what happened in the temple. Surviving Lemurians eventually work it out: instead of taking her heart, he gave his own. This is the founding act that destroys Lemuria and binds the covenant permanently.