Insight: Weapon Rune Word - Diablo 2
Insight is one of the most popular Rune Words in the entire game for Casters due to the fact that it grants Meditation Aura. This Rune Word can be equipped on an Act 2 Mercenary (since they can use Polearms) and you'll benefit from the Meditation Aura despite the Rune Word actually being equipped onto your Mercenary.
Most caster builds use an Insight Rune Word from the moment you first can make one at level 27 all the way up until max level.
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: Ral -- Tir -- Tal -- Sol
Level Req: 27
Other Req: Ladder Only
Slots: Polearms & Staves
Level 12-17 Meditation Aura When Equipped (varies)
+35% Faster Cast Rate
+200-260% Enhanced Damage (varies)
+9 To Minimum Damage
180-250% Bonus to Attack Rating (varies)
Adds 5-30 Fire Damage
+75 Poison Damage Over 5 Seconds
+1-6 To Critical Strike (varies)
+5 To All Attributes
+2 To Mana After Each Kill
23% Better Chance of Getting Magic Items