Stunned
The rank 5 commissions didn't really require hunting the golden core beasts. There were two of them within the vicinity of the city, and their presence kept the entire ecosystem balanced. They were also smart enough to not challenge the city, though they would not hesitate to act out if anyone entered their territory.
The tasks involved stuff like collecting molted scales or getting blood samples. Regardless, it was easy enough for Lex to do. Even though he noticed that the Golden core beasts had particularly strong bodies, and boasted strength above that of the norm outside of this realm, none were as abnormal as Lex. Which meant that, once again, Lex was done within a few minutes.