Vagabond Sausage posted... How is 5-2 "the last stage"? It isn't even the last area of its own world.
Third areas of any world are just boss levels. I generally don't consider them as stages. And that's the sequence i did the stages. I think most people will play 1-3 & 1-4 the moment they could due to a high soul count.
You get poisoned by the swamp, not toxicated (seriously, why didn't they go with "plague", same as in Demon's? The translation really suck in Dark Souls). Poison doesn't drain as much health. But I agree, it's annoying. Which is why you should get the shadow gear (ninja suit, not the same as black leather. It appear to work like the thiev's ring in Demon's). With it, you're able to barely get through the swamp without getting poisoned. You can find it somewhere in Blighttown. Don't remember excactly where, but it wasn't hard to find. Just pick up all the glowing item drops on the way down after the gaping dragon fight. I think you could find it right after the bonfire, halfway down.