Infinity Runeword: Stats, Best Bases & Builds
Infinity is the endgame mercenary weapon that erases elemental immunities. Here is how to build one, which base is the meta, and why Infinity shifts the entire lightning economy.
Infinity Runeword: The Mercenary''s Immunity Eraser
Infinity is the priciest runeword in Diablo 2 Resurrected, and for good reason. Slot Ber Mal Ber Ist into any gray 4-socket polearm (spear, halberd, glaive, thresher), and you grant your mercenary +2 to all skills, +50% faster cast rate, +35% faster attack speed, and most critically, a Level 12 Conviction aura that lowers enemy lightning resistance by 85%. For Lightning Sorceresses, Lightning Sorcs with Javazons, and elemental Druids that hunt lightning immunity mobs, Infinity on a mercenary is non-negotiable — it turns immunity breakers into free-flowing kill zones.
Runes Required and Socket Setup
Infinity demands four high-tier runes: Ber (highest tier), Mal (mid-high), Ber (again), and Ist (mid). The sequence is absolute: Ber, then Mal, then Ber, then Ist. Reverse them or swap any rune and the transmute fails.
| Rune | Tier | Rarity | Est. Value |
|---|
| Ber | Highest | Very Rare | 1.0 (baseline) |
| Mal | Mid-High | Uncommon | 0.15-0.25 |
| Ber | Highest | Very Rare | 1.0 |
| Ist | Mid | Common | 0.1-0.15 |
Total cost: approximately 2.25-2.4 Ber equivalents on day one of ladder. By mid-ladder, as Ber supply grows, Infinity settles around 2.0-2.1 Ber. This is why Infinity is a late-ladder goal for most players; you need to accumulate high runes before you can afford it.
Stat Breakdown and Role in Lightning Meta
Infinity is deterministic — there are no rolls. You get exactly these bonuses:
| Stat | Value |
|---|
| +2 to All Skills | Fixed (mercenary only) |
| Faster Cast Rate | +50% |
| Faster Attack Speed | +35% |
| Conviction Aura | Level 12 (mercs apply it) |
| Conviction -Enemy Lightning Res | -85% |
The Conviction aura is the game changer. Lightning immunity on mobs is binary in vanilla D2: hit an Immune and you either break it with an external source (Infinity, Lower Resist spell, Crescent Moon runeword debuff) or you reset the game. An Infinity mercenary removes that friction entirely. Every lightning-immune super unique or champion pack becomes a farm target instead of a skip.
Best Bases: The Thresher Meta
Infinity goes on polearm bases only. Polearms are two-handed weapons held by Act II mercenaries primarily, though they can be weaponswapped or held by some builds. The tier list of bases is simple: ethereal Thresher or Colossus Voulge > non-eth Thresher > Glaive > other polearms.
Ethereal Thresher is the meta standard:
- Fastest attack speed for a polearm (-50 from base speed).
- Ethereal grants +50% damage on the base (though runeword damage is unaffected).
- Durability is 15 on normal ethereal Thresher (repairs are free via any Zod rune swap or late-game Breath of the Dying).
- Damage range: 40-96 (4-socket thresher) to 60-144 (elite ethereal).
Non-eth Thresher is the budget option and what most players settle for if they cannot source an ethereal base fast. Durability stays high (40+), and damage is reliable without the glamour.
Colossus Voulge is slightly slower than Thresher but has the same base requirement. Most players skip it in favor of Thresher if a Thresher is available.
Superior rolls add 15-25% enhanced damage, pushing a superior eth Thresher to max damage potential. However, finding a superior ethereal Thresher with 4 sockets is nearly impossible on day one; most players settle for normal eth Thresher or non-eth Thresher with superior rolls.
Who Uses Infinity
Lightning Sorceress
Lightning Sorcs can solo Hell Baal runs because Infinity on mercenary breaks every lightning-immune pack in their path. Throw a second Conviction aura (cast via skill points or a swap item) and you stack aura effects for even faster immune clearing.
Javazon / Lightning Amazon
Physical + Lightning hybrid Javazons (or pure Lightning builds) lean on Infinity to clear light-immune packs. The Javazon''s javelin bounces off walls and crowds, and Conviction''s resistance debuff turns skippable packs into viable farm targets.
Elemental Druid or Hybrid Caster
Any Druid or caster mixing elements (Fissure, Tornado, Frozen Orb, etc.) benefit from removing immunities. Infinity is less essential for elemental hybrids than for pure Lightning Sorcs, but it accelerates endgame farming.
Summoner Builds (Necro, Druid)
Summoners do not scale as hard from Conviction as Lightning builds, but the +2 to all skills (mercs level up too) and +50% FCR on the mercenary can push your mercenary''s spell-casting speed or attack speed past important breakpoints.
Budget Alternatives and Upgrade Paths
If you cannot afford Infinity early, Pride (Cham Sur Io Lo) is the budget mercenary word that grants Concentration aura (+2 merc skills, faster attack speed, physical damage boost). Pride is more affordable (roughly half Infinity''s cost) and works for physical-based builds. For lightning immunity specifically, there is no real substitute — you either get Infinity or you skip light-immune packs and use a second Conviction source yourself.
Upgrades beyond Infinity are rare. Some endgame players build multiple Infinities on separate mercs or swap bases for ethereal variants, but the runeword never gets replaced. The investment is permanent and unquestionable.
Cost and Trade Value
Infinity pricing is the most stable in the ladder economy because the rune cost is pegged to Ber rune scarcity.
| Ladder Phase | Approximate Cost |
|---|
| Week 1 (day 0-7) | 2.5-3 Ber (rune drought) |
| Week 2 (day 8-14) | 2.25-2.4 Ber (first supply bumps) |
| Week 3-4 | 2.0-2.15 Ber (settling) |
| Week 6+ | 1.75-2.0 Ber (steady supply) |
Your Infinity does not depreciate because it is not a flex item — it is infrastructure for Lightning Sorcs and their mercenaries. Once you own one, you own it for the season. Trade value is stable because every Lightning Sorceress, Javazon, and endgame elemental build needs one; the demand is literally infinite (pun intended).
A Lightning Sorc with Infinity can farm Chaos Sanctuary and Baal runs at competitive speeds compared to Fire Sorcs with Enigma. The mercenary becomes the speed enabler.