Hey so me and this fireteam were fighting atheon and we tried to kill him in the first times vengeance. We succeeded in doing so and also had damage on atheon from the relic. We went through the portal which we were not teleported into before killing oracles etc. We did not become marked by the void. We were free to explore. Eventually we all died from falling trying to climb what looks to be a tree that is climbable to higher area. Someone must stay outside in the present to keep us from getting lost in time. I dont know if anyones done this or can debunk that there is no chest after killing atheon by this method but we were not marked inside the portal. Please feel free to send me a message on xbox gt L Darth Heff L.