My guess is that Zaros stops it. But, that would assume that FOTG is a "past" quest, that all players have already done lore wise. Everything up to and including TWW is already 'done'. FOTG is not. A brand new account has already seen Guthix die, but has not met Zaros until they have done FOTG I did a lot of Mahjarrat quests before I did ROTM where their "new" faces/clothing (if you paid attention during the quest you'd have seen that once the ritual was completed by killing someone, they looked different). So once I realized that I should have done ROTM BEFORE all of those quests means I did them in the wrong order (not that it matters to me) They can't make it perfect.