Darren G. Davis 
Wrath of the Titans #3 [EPUB ebook] 

As the gods conspire against him, Perseus‘ quest to recover his beloved son and heir to the throne of Argos is thrown into peril. From the volcanic depths of Mt. Aetna, the whirlwinds blow one of the fiercest demons into his path… Typhon, whose hundred, horrible heads touch the stars, whose blackest eyes drip venom, whose gaping jaws pour lava and red-hot stones. Perseus may be the son of Zeus, but he will need more than the blessings of Olympus to defeat this monster. But help does come from an unexpected source from the past.