Man Vicar Amelia has to be the easiest boss I have faced so far. Just throw an urn of oil, spam molotovs, use fire paper, and stay close and hack the to death with the cleaver. So much easier than the Blood Starved Beast or Father Gascione, and a bit easier than even Cleric Beast. She is the only boss I have beaten on the first try so far. Eileen the Crow has still been by far my most difficult kill in this game, though I'm sure it'll get a lot worse later on by this game's reputation.