*This is not in terms of the game, but canonically.*
The situation is a Battle Royale, all heroes have the equipment they have in game, but we're going by lore as it appears. It doesn't start off at a Cornucopia, but rather they are all equally spread out in a large, urban area. No teams, it's mano a mano, each man for himself, each hero starting off alone.Groups are allowed to form, but in the end there must only be one winner.
They are randomly thrust into this area with the knowledge that this is a battle arena against 20 other heroes, but given no more information than that, so clearly lore-based wits and attributes apply here. Less of an emphasis on survivability, let's assume food, water and disease etc is not a factor here, it's a battle arena, not a survival contest.
So, in this random battle arena, Battle Royale style Hunger Games, who do you think would be the last man surviving?
Your vote: Symmetra