In your answer to justanotherfandomjunkie, your first picture shows the unknown assassin saying "I will see to the rest." Do you suppose he's talking about clearing out any servants who might be present? Or has he hidden in the house, waiting for Ciel and Sebastian to return? In which case we may see quite a fight next ish
I think the attacker is talking to the person with the gun and just tells him that he’ll take over the job of fighting Agni now. When Agni appeared the fight would have probably been to difficult for the guy with the gun so the other one came to help. If the person with the gun was Sirius and the one with the knives was Polaris I guess the butler (Polaris) came to assist his master.
So I don’t think he’s talking about another job but only about the situation in this scene.