You can. Just need a fire nearby. A fire that Moder cannot extinguish. So yes, it does require a bit of cheese.

And I really have no idea how you will survive Yagluth. Because arrows don't do jack to him, so it will probably take RL days to down him with flint arrows (the highest you can go) whereas he just needs to look at you and you're dead in a second.

Edit: Swamps will REALLY be a challenge just in deer skin. Forget about shields, so you either go pure HHH (triple health) to at least survive a hit, but then die quickly because you have no stamina left, or you go SSS (triple stamina) to be able to run away as quickly as possible, but have absolutely no health.

Pretty much bows only, as you can never get in close quarters combat, as any enemy starting with swamps will be able to kill you with one hit (at the most two). And that bow will be a crude bow. Because... no cheese! :D

If you are very young and still have reflexes you might be able to survive playing a rogue character who is constantly on the move. You need to master dodging to perfection to be able to do that.

Remember, that would be flint knives, unless you go with the much more preferable abyssal dagger.

I mean, I can sort-of survive in the plains with root armor, but you can't even get that, as it requires swamp materials. And I could only do that because I had access to swamp and mountain food.

That's a really tough one. :D

Eikthyr is a piece of cake.

Elder should be not much different from how you do it normally, instead of troll armor you still have deer. Instead of a fine bow, you have a crude bow. Fire arrows are the same. So, multiple bows in case one breaks, and LOTS of arrows.

Bonemass I can see, you need an elevated platform to avoid the poison and then shoot arrows in its face till your bow breaks.

Moder will be VERY tough, since it is really hard to avoid her ice blasts and you pretty much need to dig beneath her altar to put a fire there she can't extinguish. But it should be possible. Again, multiple crude bows are a must.

Yagluth? I have no eff'n clue on how to face this guy. No clue. ;)

Last edit: The main challenge are not the bosses, but to GET there. To gather the materials to spawn them, to survive the biomes they... live in, I suppose. THAT is the challenge.