Ah, it wasn't Narcissus in the box. He just went into a room with Chimera and didn't come out. The person who I was thinking of was the werehyena Ajax ("they cut his arms and legs off and burned the ends of the wounds so he wouldn't heal the damage. Chimera said they'd put him in a metal box and just get him out on special occasions.")

Narcissus was apparently being tortured and was gagged; it's right at the end that they acknowledge he's still alive and apparently pregnant, which is where the breeding comment came in.