Yiannis Cirillo and the Titans Book 1 & 2

Some people say the greek gods were myths, but they're indeed real. Their children grow up to be heroes, some even becoming famous in the mortal world. However, if the gods exist, then so do the monsters and all those ancient beings from eons ago. One of them, a Titan, is eager to rise from the depths of Tartarus and get his revenge on the gods. This Titan's son, Yiannis, a fourteen-year-old boy, is just as dissatisfied with the gods. Joining forces with his father, he seeks to recreate the world based on his ideals.