A/N this chapter is dedicated to........ MountainMama229 !
Leo always felt responsible for everyone's problems, so in a weird way, he felt responsible for Calypso being trapped on her island. So, when the raft arrived, his love for Calypso and the thought that he was responsible for her being stuck here was too much, so he had to swear on the River Styx that he would come back for her. Luckily, the gods were nice, so he did save her, after the war with Gaea and was finally released from his misery of not being with his love and the pain of feeling responsible for her's.
A/N idk that just happened.... So yeah. -Piper