Revenge
Amynta's heart lurched when she heard this, but her lips were sealed, both by design and by her will. However, Leonel didn't really need to hear the answer, he already knew it.
In this regard, Amynta and his grandfather weren't all that different.
Leonel had many thoughts about where his grandfather might be and what he was doing now. There was no reason for him to have been gone so long, it didn't make any sense, especially considering the time dilation between the regions.
However, seeing how far Amynta had gone to revive the Constellation Families, he had a guess.
When Leonel left, the Fawkes family barely had any members.
Other than himself, who was already barely considered a Fawkes to begin with, there were only his grandfather, his mother and his uncle.