Infinity Thresher Ethereal 255-299% ED

50% Chance To Cast Level 20 Chain Lightning When You Kill An Enemy
Level 12 Conviction Aura When Equipped
+35% Faster Run/Walk
+255-299% Enhanced Damage
-(45-55)% To Enemy Lightning Resist
+40% Chance of Crushing Blow
Prevent Monster Heal
0.5-49.5 To Vitality (Based on Character Level)
30% Better Chance of Getting Magic Items
Level 21 Cyclone Armor (30 Charges)

Infinity is the rune word 'BerMalBerIst' for polearms in Diablo II: Lord of Destruction and also in spears in Diablo II: Resurrected.

The Conviction aura provided by Infinity maximizes the effects of the high-level Chain Lightning that the weapon produces. For nearly every character that deals elemental damage, this is the best mercenary weapon since it actively reduces resistances, vastly increasing the damage output of the character. Only builds that deal magic damage, poison damage or physical damage (with the exception of moves that deal with defense values) do not receive significant benefit from the Conviction aura on this weapon.

The decrease in enemies' Lightning Resistance only works for the character equipped with it, so Lightning-based Sorceresses with an Infinity-wielding Mercenary will only benefit from the Conviction aura. Sorceresses who use lightning spells may even want to wield Infinity themselves to make use of the massive enemy lightning resistance reduction, or opt for Crescent Moon instead.

Infinity is a prized weapon because it requires two Ber runes and can only be constructed by Ladder characters.