Taking a break from his war against the rats, Merlot visited the scarred naturalist to hold up his end of the deal on info. Trading the freshly slain rats, he was told many things about the creature, how it smothered its prey in its wings, fangs that could break off and kill victims days later, its taste for royal blood, and how it may have existed for thousands of years. He didn't quite understand the significance of a "second city", but he was glad for the information.
The next day he resumed his efforts in helping the Clay Coalman. He bared his fangs and showed his fists at the right people, eventually tracking down the culprit and giving him his just desserts. Afterwards, when he returned the stolen secrets to his clay friend, he advised him to support the revolution. Bringing another clay man might subject him to the same persecution, so it would be wise to befriend those who stand against such things. The coalman agreed and was happy to help the revolution, even if he didn't completely understand their ideals.
Afterwards, he returned to his lodgings to resume his war against the Rattus Faber, with thoughts of the Vake in the back of his mind. Even though he was a vampire, Merlot wouldn't stand a chance against such a beast. He was no undead lord with hordes of minions, he was a vermin hunter living in a smoky flophouse. He would need to hone his skills to even survive an encounter with such a beast, a challenge he willingly accepted. He hoped that his beloved Erasmus, wherever he was, would be proud of him.
Further notes: Merlot fought hard against the Rattus Faber. It turned out that they were using his dwellings as a stash house. He faced off against their chief, but decided to spare the rodent. He fought admirably and had no reason to take any more rodent lives, his debt to the scarred naturalist had been paid already. Perhaps the bandit chief could find some manner of redemption? After all, rats are people too.