Hi (i dont have Oblivion yet). I have heard that in Oblivion the monsters level with you. So i wonder just how much this afflict the game. If i start a stealth type character and only level in skills like sneak and security, will the monsters become stronger than me? Is it possible to become a quite good fighter as a thief or will the monsters level away and become more and more difficult for every level?

Everything levels up, to a certain extent, but you have the options of more ways to fight each enemy in whatever way that gives you the most advantage ... find the best way and tactic and you will win. Also, you improve you abilities so much more, the more you level, that by comparison the enemies will seem to become much weaker and less of a challenge, in fact you can become almost god-like .... it's more fun though if you don't become god-like and don't use all the power that you could use if you wanted to. So basically the answer is that everything becomes easier. Enjoy.

Thanks alot . That exactly answered my question.

What I usually notice actually, is that at a certain point in leveling, the monsters are actually a lot tougher and I had a lot of difficulties. But Sitruc is right, eventually you will level to a point where the monsters become easier for you.

Yeah yesterday i ventured into my first Oblivion gate (at char level4) but eventually i got killed by this massive Daedra looking guy, so now i think i must buy some potions or stuff before trying it again. Can it be my build that makes it more challanging? I have light armor,sneak,marksman,blade,block,acrobatics,and security. I probably just have some lousy equipment.

All those stealth skills will get you killed if you don't use them. The idea is to use your skills to your advantage, because they will be higher than normal. You should sneak around more to get sneak attacks and use your bow more often to avoid damage. Light armor isn't really supposed to be taken into combat, and if it is, you're supposed to use speed to avoid hits.

yeah you got a point there.But it seams like the main quest is made for a fighter (this far.i haven't gotten verry far). Like when you are to free that town (Kavach something) everyone is just charging into battle so it's little time to sneak.If i sneak attack one of those flame Atronachs they still got alot life left and then they burn me with their spells.

Getting better equipment will help a bit, from the likes of bandits you kill in places such as caves, mines and ruins, the bandit boss usually has the best armour and weapon, the best there is for that level. You may also pick up a useful ring or amulet that restores health a bit or gives a bit of shield protection, there seems to be plenty of these around. All give that little bit more edge.

Health potions as well, buying or make with alchemy, and you also find a lot of these.

Some first-level alchemy ingredients, buy or find:-
Cairn Bolete Cap, Location: Caves and other places.
Lady's Mantle Leaves Location: Goldcoast, Colovian Highlands and other places.
Mugwort Seeds, Location: anywhere
Venison, Location: Wilderness mostly.

Myself, I wasn't thinking of doing the main quest until much later when I had built up my character, but there's no reason why you shouldn't. It was just my choice.

Ok thanks for the tips. I think i will try making some potions by those ingredients.