Early on, and before even there was a war between titans and gods, a deformed god was born, and because of his ugly appearance, Adonis released him in space. Later on, Terra found him and took care of him regardless of the fact that he was a god. she treated him as her child just like luna her daughter, luna and hephaistos grow up like siblings, shared love and knowledge and took care of each other. Furthermore, turned out Hephaistos was the son of Adonis, he had incredible powers of fire, he was gifted in metal working and knowledge about weapons. After along time, Hephaistos decided to prove himself, he created ten thousand soldiers with strong weapons and invaded the domain of gods, but it was not enough to kill not even a single god. Hephaistos only wanted to impress gods and show them that he deserved more then anyone else to be considered as one of the four main gods of (domain of gods). Hephaistos finally got his recognition, thus, he built a huge castle made of gold and diamonds, and also made some phenomenal weapons for Adonis and other gods. Not because he was forced to do so, but because he wanted to gain their trust. As a preparation to what coming next.
Regardless of what hephaistos did for his father Adonis from creating weapons and being beside him during wars against titans, hephaistos always hated Adonis and his policy. Moreover, all what he carried about is to one day collapse the domain of gods on Adonis's head. A darken hatred in his heart was never meant to end until it reaches its purpose. Terra supported him, all titans did, and apparently, the six thousand years of chaos and events was all planned by hephaistos, including the loss of titans in war, Adonis's usage of the Purple Stone to create humans, and also to show other gods that Adonis only cared about himself and his desires. Lissandra knew that hephaistos was a traitor but she did not talked about it. Sunnus did not trust Hephaistos at the beginning, but after he had no choice but to do so.