Ok so im trying to do it so that i can get both rewards, the Armor of the Old Gods, and the Silver Blood Family Ring.

So i wait for the moment after Madanach rewards me with the armor, and the other forsworn have ran outside. However when i attack Madanach, not only do the other forsworn come back but several city guards and even Thonar come in as well, and they don't attack any of the forsworn right next to them, but me. I don't know why. The problem here is that i then have to kill Thonar which means i can't get the ring, also killing him and the city guards attacking me causes a bounty to be on me, therefore once i complete the quest this way, not only did i never get the Ring, all the city guards are hostile to me.

I was planning on the forsworn coming back after i killed Madanach, but i never planned on Thonar coming in as well. How do i prevent him and the city guards from coming in?