Being the titular twist of Survivor: Ragnarok, this twist provides an opportunity for voted out castaways, known as 'zombies' to influence the game in progress, by duelling a former tribe-mate for the chance to vote in their stead at the next Tribal Council, before facing the next person voted out as usual for the right to remain that tribe's zombie. At a predetermined point in the game, the reigning zombie for each tribe re-enter as fully-fledged castaways, to continue their pursuit for the title of Sole Survivor.
Once a player is voted out, they go to Ragnarok Island as a ‘zombie’. The next time their former tribe loses an immunity challenge, the current zombie must challenge one of their former tribe-mates to a Vote Duel. If the zombie wins, they will get to unprecedented ability to cast a VOTE in the duel loser's stead at the upcoming Tribal Council. If they lose this duel however, they are out for good.
If the zombie is successful and survives, they must still participate in the Zombie Duel, against the newly voted out castaway from that Tribal Council, for the right to remain the zombie for that tribe. This means there will always be one zombie on Ragnarok Island per each tribe in the game, and they will only ever face their delegated tribe’s vote-outs, not one another.
This means there will be either one or two duels each day. The Vote Duel always happens every day for the reigning zombie on the losing tribe, whilst the Zombie Duel only occurs if the reigning zombie was successful in the previous Vote Duel, and must duel the incoming resident. Vote Duels are non-live until Tribal results - so players must plan in the event that either their tribe mate or the reigning zombie will voting. Zombie Duels (if applicable) are live after each Immunity Challenge.
At a point in the game, the last standing zombie for each tribe will re-enter the game to continue their quest for the title of Sole Survivor.
Since zombies only ever compete if their own former tribe loses, it is possible for someone to survive Ragnarok and re-enter the game after elimination without having to duel, if their former tribe doesn't lose another challenge.