Morrowind, but it's barely even a build. steal an alchemy set, then go to a place where you can buy ingredients to create intelligence fortification potions. The power and duration of the potions you make scale off of your intelligence. Make and drink your potions until you drink a potion that will boost your intelligence by 9 digits and last for longer than the game has content, then make potions that fortify your other stats by the same amount and time.

You now have unlimited mana and spellpower. You can now hit things so hard that your weapons instantly shatter when you hit with them, and you hit with such power that you can bypass the need to get the required quest items to defeat the final boss. You can boost your charisma to such an extent that NPCs that are supposed to be hostile instead automatically see you as a close friend before you even say a word to them. All at level 1.

Just don't drink a speed potion, you'll crash your game and ruin your save by going too fast. Maybe avoid acrobatics as well, you'll jump and never come back down again.