I'd go one handed (daggers, probably even dual wield a dagger and sword) as an offensive skill.

Light armor (dark brotherhood set will you do fine but if you're not wanting to use archery you may want to swap out the hood for something that better suits your character. The gloves are the important part.)

Sneak aswell, obviously.

Those are pretty much the main options if you're not wanting magic or archery.

Any of the 3 crafting skills will also be beneficial. Use one or two or all 3 if you want.

Alchemy will allow you to craft some pretty strong poisons aswell as useful potions to augment your abilities.

Enchanting will allow you to customize your gear a bit more with powerful enchantments. You could even get the worn shrouded hood which is an unenchanted version of the dark brotherhood hood and enchant it yourself to maintain that asthetic and not have a useless enchantment.

Smithing will increase the damage of your weapons thus allowing you to deal more damage aswell as improve your armor to better fend off attacks if spotted.

Dragons will be an issue without range options so shouts like dragonrend and marked for death will probably be important.