Nadir: Helm Rune Word - Diablo 2
Nadir is the lowest level Helm Rune Word in the game (along with the lowest level Rune Word in general). It offers a small amount of defensive bonuses, Strength and Mana After each kill. You'll also find -3 to Light Radius and -33% Less Gold from Monsters. The Gold from Monsters isn't too big of a deal at this low of a level since they don't drop much anyway but the - Light Radius is a big bummer.
Keep in mind that all Rune Words you create will retain any pre-existing bonuses found on the item. If you find a 'Superior' piece of armor with +Enhanced Defense, a Superior Weapon with +Enhanced Damage or a Helm/Weapon that has +Skill bonuses for a certain class, all of these will remain on the final Rune Word that is created. It's also possible to 'ebug' a piece of Ethereal Armor that you find which will increase the Defense bonuses by 50%, check out my Ebugging Guide for more information.
Farming High Runes: Out of all locations in the game one stands above the rest for farming specifically High Runes, the Countess during Act 1. The Countess has a guaranteed chance to always drop a High Rune and can even drop more than one. Check out my The Countess Farming Guide for more information.
Required Runes: Nef -- Tir
Level Req: 13
Other Req: N/A
+50% Enhanced Defense
+30 Defense vs. Missile
+5 to Strength
+2 to Mana after each Kill
-33% Extra Gold from Monsters
-3 to Light Radius
Level 13 Cloak of Shadows (9 charges)