Servatius Quintilius is a Guard Captain of the Imperial Watch in the Imperial City. He takes over Hieronymus Lex's post after Lex is re-assigned to Anvil, but he doesn't believe in the Thieves Guild or the Gray Fox.
Usually he patrols the Imperial City Waterfront District and goes to the The Bloated Float. He sleeps in the South Watch Tower (Captain's Quarters). He is newly appointed a Captain of the Imperial Watch so will turn down the Hero's offer of arresting another Captain.
While the Captains of the City Watch are sworn to protect and serve, it is known by those under Audens Avidius's watch that he is corrupt. By law, the only person who can arrest a captain is a captain, and even then nobody is willing to come forward to press charges.
Hieronymus Lex is still a constant thorn in the side of the Thieves Guild. As the rules of the guild forbid killing, the plan is to have him restationed to Anvil where he can do little harm to the guild.