Hephaestus is only one who can get answers from Lethe, so he'll punish her, bend her, use her. Until she gives him everything.

There are so many things Lethe can't remember. The gods she hurt. The gods who hurt her. Most importantly, she can't remember the location of the knife she needs to trade for her freedom. She doesn't want to, happy to remain in the darkness and silence, forgotten.

When the other gods drag her from her prison, bent on answers, she finds herself faced with Hephaestus. A god she shouldn't remember, but does.

He wants to play a game, but Lethe is done playing. That's why she'll win.