If we’re talking about longest span of time, not necessarily most total hours. Then it would be RuneScape. Started playing back when the wild had no protections. Then after all the changes they made, and once OSRS came out, I went to that instead. Just got my 20-year cape on rs3
Hmmm, you could just… leave them submerged in the oil? Would that protect them from the smoke? I don’t know. I’ll have to look into these “underwater” builds though because that does sound cool.