Ignacio is not new. He was in several episodes last season. He was introduced as a guard with a gun at the entrance to the tunnel in the back of the maternity shop. He is a funny character. His banter last night pleading with Nancy to kill Roy Till because Till's a killer and Ignacio is not was hilarious. He finished by telling Nancy that if she saved Ignacio, he would kill Roy Till for her. That was very funny dialog.
Your observation that we didn't actually see DEA Captain Roy Till get killed last night is keen. I'm skeptical that he's dead. He could return and kill Esteban yet for all we know.