Percy Jackson
Hephaestus: Is grateful to Percy for having discovered who was using his forge under Mt. St. Helens, even though he causes an eruption that destroyed the forge and awakened Typhon (who had been imprisoned under it), but also dispersed and/or killed the users. At the end of the 5th book, Hephaestus said that Percy had done a 'Pretty bang up job, mostly'. Historically, Hephaestus and Poseidon have close ties in the terms of the Cyclopes who work for both of them.