https://screenrant.com/percy-jackson-season-1-book-arc-story-rick-riordan/

Percy Jackson and the Olympians author Rick Riordan teases how season 1 is already foreshadowing a "five book arc" for the Disney+ adaptation.

Percy Jackson Episode 4's New Character Reference Teases 2 Huge Storylines That Disney Won't Pay Off For Years (https://screenrant.com/percy-jackson-episode-4-grover-pan-future-storyline-tease/)

Percy Jackson and the Olympians episode 4 mentions a mysterious new character, one who sets up two major storylines for the future of the show.