From Diablo Wiki
Mercenaries are NPCs players can hire to fight alongside them. While Mercenaries were largely a novelty in early versions of Diablo II, they are substantially upgraded in Diablo II: Lord of Destruction, and can be quite effective when properly equipped and supported.
- See the Mercenary Guide for detailed strategy, skill, equipment, and much more information about Mercs.
There are four types of mercenaries, Rogues (Act 1 archers), Town Guards (Act 2 spear carriers), Iron Wolves (Act 3 sorcerers), and Barbarians (Act 5 warriors). Players can only use one mercenary at a time, and hiring a new one permanently dismisses the current merc.
Mercenaries can be outfitted with weapons (of the appropriate type), body armor, and headgear, and they benefit from most of the same bonuses that your characters enjoy. Mercenaries have inherent stats and bonuses as well, and can survive without quality equipment, though the combat mercs are basically harmless without a good weapon.
In v1.10+, mercs are all available for hire at levels near those of your character. In earlier versions of the game, they were often much lower, and newly hired Mercs had to be leveled up extensively to make them useful and hardy enough to survive, especially when obtained on Hell difficulty.
 Act I: Rogue ScoutsKashya in the Rogue Encampment. (She gives one as a reward for completing the Blood Raven quest, and will hire them after that point, or to any character over level 8.) Rogue mercs are ranged attackers who use bows to attack from a distance. They are fairly fragile and must be kept from harm, but can dispense solid artillery support from behind the front lines. Their AI largely keeps them from harm, but they can be come confused as to how far they should stand from the action, and will sometimes wander back and forth uselessly.
These rogues may add fire or cold damage to their arrows; this option is only visible in the hiring window, and makes little difference to their overall damage, though the cold can add a useful chilling effect, especially in the early going when new characters need all the help they can get.
- Skills: Cold Arrow/Inner Sight or Fire Arrow/Inner Sight
- Allowed Equipment: Armor, Helms, Bows (no Crossbows or Amazon-only bows).
 Rogue Merc Names
The names are randomly selected each time a list of mercs for hire is generated; the names do not have any connection to their other abilities or damage types. As is the case with lots of weapons in the game, and especially with the names of NPC mercs, the Blizzard North designers worked in the names of Blizzard employees, and notable members of the Diablo II fan community. This was taken to an extreme with the Rogue mercs, as seemingly every male Blizzard North employee worked in their girlfriend or wife, and every Blizzard North female employee threw in her name or alias. Fans were honored too, Elly and Gaile were webmasters of Diabloii.net, as was Flux (found in Act Three).
 Act II: Desert MercenariesGreiz in Lut Gholein. They are melee attackers and use spears/javelins or polearms to great effect. These mercs are the most popular hires in the game, since they come with various auras that can greatly benefit their employer.
Skills: Jab attack.
Auras: These mercs have a variety of auras. There are three types available on each difficulty level, though the auras found on Normal and Hell difficulty levels are the same.
- Combat (Normal): Prayer
- Combat (Nightmare): Thorns
- Combat (Hell): Prayer
- Defense (Normal): Defiance
- Defense (Nightmare): Holy Freeze
- Defense (Hell): Defiance
- Offense (Normal): Blessed Aim
- Offense (Nightmare): Might
- Offense (Hell): Blessed Aim
Allowed Equipment: Armor, Helms, Spears, Polearms, Javelins (Used solely for Amazon-only javelins or spears.weapons.) They can not equip
 Desert Mercenary Names
The names are randomly selected each time a list of mercs for hire is generated; the names do not have any connection to their other abilities or aura types. As is the case with lots of weapons in the game, and especially with the names of NPC mercs, the Blizzard North designers worked in the names of Blizzard employees, and notable members of the Diablo II fan community. Azrael was the webmaster of Diablo2.com, a prominent fansite in the pre-Diablo 2 days.
 Act III: Iron WolvesAsheara in the Kurast Docks. These are the only magical mercs, and each one specializes in Lightning, Cold, or Fire. Their AI is similar to that of the Rogue mercs and they tend to stay behind the lines and attack from a distance, even though they carry shields and can achieve fairly high defense and resistances.
Each Iron Wolf is either fire, lightning, or cold based and although they can each use two or three spells, this only adds slightly to their variety.
- Fire: Inferno or Fireball.
- Cold: Glacial Spike, Ice Blast, and Frozen Armor.
- Lightning: Charged Bolt and Lightning Bolt.
The cold are the most popular, since that element has the effect of chilling and slowing targets, but the damage dealt by the three types is equivalent.
Allowed Equipment: Armor, Helms, Shields and Swords
Notes: Iron Wolves very rarely hit anything with their weapon, so are best equipped with a sword that has spell-caster bonuses.
 Iron Wolf Names
There are quite a few tongue-twisting names available for Iron Wolves. One is randomly assigned to each of the Iron Wolves your character sees on the hireling menu. As is the case with lots of weapons in the game, and especially with the names of NPC mercs, the Blizzard North designers worked in the names of Blizzard employees, and notable members of the Diablo II fan community. The last 3 Iron Wolf names (they are listed in this order in the game database file, making it clear that the honored fans were added last) are all fans; Jarulf is the author of the famous Diablo guide. Flux was one of the webmasters of Diabloii.net (co-webmasters Elly and Gaile both showed up as Act One rogue mercs). And Scorch was the author of the first monster specialty site, Darkness, which was hosted by Diabloii.net.
 Act IV
There are no Mercenaries available for hire in Act Four, though Tyrael will resurrect fallen Mercenaries retained from other acts.
 Act V: BarbariansQual-Kehk in Harrogath once you have completed the Rescue the Barbarians quest. Unlike Kashya in Act One, he does not reward you with a free barbarian merc.
- Skills: Bash and Stun
- Allowed Equipment: Armor, Helms, Barbarian Class-specific Helms, One Sword (can't dual wield).
 Barbarian Merc Names
The names are randomly assigned to each of the Barbarians when the hireling menu is generated. As with the other mercs, Blizzard North worked a lot of employee and friend names into the list of Barbarians, and honored a few fans as well. Varaya and Khan were two of the best known mod-makers from the days of Diablo, famed for their well-made Lord of the Rings-themed mods. Lanth was another of the early staff members of Diabloii.net, but likely earned his merc name by being a regular in the Diabloii.net chat room, which was regularly frequented by Peter Hu (AKA Isolde, see the rogue merc names), the chief architect of the v1.10 patch, in which Lanth's name was added.
 v1.13 Barbarian Merc Name Change
The v1.13 Diablo 2 patch "updated" the names of two of the mercs. As players who dug into the game code informed us:
- In 1.13, MercX136 is called 'Klar', in 1.12 it was 'Weohstan'.
- In 1.13, MercX135 is called 'Tryneus', in 1.12 it was 'Erfor'.
There's not yet any known reason for this change, though speculation is rife. The leading theory is that this is related to some plot/story elements of Diablo 3. We'll see Barbarian NPCs named Klar and Tryneus, or they'll be mentioned in dialogue or otherwise involved. Perhaps they've become leaders of some Barbarian city, in the 20 years between D2X and D3?
The fact that there was a mention of the name update in the patch notes seems to hint that it's important, or at least worth noticing. If Blizzard didn't want players to know about the change, they could have not mentioned it, or simply deleted "Weohstan" and "Erfor" from the list of names if there was a problem with them.
Other theories are less imaginative. Perhaps those are the nicknames of two of the Blizzard v1.13 patch programmers? Maybe the original names are dirty slang in some language? Maybe some Blizzard employee got bored after seeing the same NPC names for 7 years and wanted to make a change?
 External Links
- Spirea's Hireling Stats Calculator - If you need to know the stats of each level of the hireling.