Arthur was a vampire and someone who trained with the special techniques of the Blood Monarch. So, tracking two people was easy, especially Jake, someone who had a mark after selling his soul to Arthur.
He ran away from where the battle occurred, going as fast as possible because there was a chance the Bishop would know about that and would go after him, which would be a disaster.
Also, his fight with the priests did not last long, so it took Arthur fifteen minutes to catch up with Agatha and Jake, who were surprised to see Arthur there so quickly.
"Are you done with the fighting? How many were they?" Jake asked, gasping his mouth.
"Five, I killed three. Now, let's keep moving, or else the Bishop has the chance to find us."
They nodded and kept moving toward the forest, into a location humans never went to. Dangerous, mysterious, and also the home of the elves. Agatha was sure there would be no way for the church to find them there and reassured Arthur and Jake multiple times.