What are Mercenaries and why do I need them in Vessel of Hatred

One of the key new features coming in Diablo 4, Vessel of Hatred is the new Mercenary system. Unlike the follower system in Diablo 2 or Diablo 3, you will need to level up and gain renown with your Mercenaries to fully unlock their potential. They each have significantly different options available to them, and need to be levelled independently to gain renown.

Who are the Mercenaries and how do I get them?

Vessel of Hatred ships with four different Mercenaries to find and recruit. Your choices are:

• Raheir, the Shieldbearer — Born to the lawless and rough streets of Gea Kul and trained by the Iron Wolves.
• Varyana, the Berserker Crone — Former cannibal who left her tribe when they started dealing with darker forces; butcher by trade turned mercenary.
• Subo, the Bounty Hunter — A disgraced Archer from the mountains, shunned by the same people who had looked to him for salvation and now a bounty hunter for hire.
• Aldkin, the Cursed Child — Half-child, half-demon creature born part demonic due to the influence of the First Khazra from the Citadel performing dark rituals on his mother.

You will need to unlock these via a series of quests.

Raheir

You meet Raheir very early in the Vessel of Hatred campaign, following along with the main quest line unlocks him shortly after you first enter Nahantu. Unlocking him also unlocks the Mercenary’s Den and Raheir’s Anvil, which gives you access to a blacksmith while in the Den.

The Den acts as a personal hub, when fully unlocked it has a number of crafting vendors, a Waypoint, and it is where you choose which Mercenaries you have assigned. Unlocking the Den also starts quests to find and recruit the other three Mercenaries.

He is a tank style companion, whose main role is to soak damage and taunt enemies away from you. Excellent for classes that are a bit squishy.

Varyana

Temple of Rot
Revenge
Maybe I’ll be back.
Don’t touch the meat.
— Varyana

To unlock Varyana, you will first need to complete the Temple of Rot stronghold. Most of her quest chain happens in the Dry Steppes. Fixated on revenge, Varyana will not listen to reason until her enemies have been defeated. You will then need to convince her that she can still contribute value back at the Mercenary’s Den.

Her primary skills revolve around giving you rapid movement and stacking damage.

Varyana is the only Mercenary that did not unlock additional features within the Mercenary’s Den.

Subo

Raheir,
My quarry’s trail leads to the Fens.
I hope the bird finds you in time.
He’ll bring me your response.
S.

To unlock Subo you need to travel to Hawezar and find where he has hidden. He will enlist you to help him in a rescue mission. Once that is complete he can be convinced to join you back at the Mercenary’s Den. Once he does, it unlocks the Guild Coffers, which gives you access to your stash. And a Rings and Amulets vendor in the form of a box of treasures, allowing you to see things.

This bounty hunter attacks from range and deploys trays to slow your enemies or make them vulnerable. He also has a handy skill to show nearby enemies and resources on your minimap.

Aldkin

I hold myself accountable for my son’s curse. He will never be rid of it, though his heart is pure.
Even now, e’s drawn to the Dark Citadel.
He speaks of a passage hidden in the vines and rock.
What he hopes to find there, I do not know.

Aldkin is an orphan child cursed by a demon haunting the remainder of his family. You end up playing hide and seek to discover the cause of recent unrest near where his family had previously lived. After finding his possessions and the graves of his parents, you tempt his out of hiding and reassure him.

Once you convince him to join you at the Mercenary’s Den, he unlocks a the Cursed Toy Box which acts as an Occultist.

How to hire your Mercenaries

When adventuring solo, you can have two companions assigned to assist you. All mercenaries are hired from within the Mercenary’s Den. To hire one you interact with the desired companion and you will be offered two menu options: to hire them as a Mercenary, or to hire them as a Reinforcement.

The more powerful of the two companions will be the Mercenary. As you level them up you will unlock their skill tree to enable them to provide substantial aid. As you level up you will need to make choices between pairs of skills down a tree with one skill per tier, in a linked path, until you reach the bottom. When fully unlocked they will have five skills they can use to assist you. New skills are unlocked as you gain renown.

Your Reinforcement isn’t quite as powerful, but will steadfastly assist you as required. You will need to chose one of their available abilities, and then chose a condition that will trigger when they will come to assist you. Examples of trigger events include: when you enter combat, when you take damage, or when you become crowd controlled.

If you are in a party with other people, your Mercenary takes a break, but your Reinforcement hangs around to keep an eye on you, and still shows up when their condition is met.

How to level your Mercenaries

Your Mercenary companions will level up by following you around while you complete quests, and kill enemy mobs, anything that rewards you XP will also reward them with XP. The assistant in the Mercenary slot will level faster than your reinforcement when adventuring solo. They take a break while you are in a party. You can always see which assistants you have chosen, in which slot, by looking at the lefthand side of your screen when quest NPCs appear.

The assistant listed first with the green icon is the Mercenary, the character listed second with the white icon is the Reinforcement. They have purple XP bar, and show their current renown level next to their name.

When they gain a level of renown, you will get an onscreen toast to tell you. You can then access the Mercenaries interface at any time to see the progress of your mercenaries by using the default keybind shift-M on PC, or by using the Mercenary button on the top right of the Character pane.

The Mercenary pane also gives you a shortcut to teleport to the Mercenary’s Den from anywhere.

Each Mercenary companion has 10 ranks of Renown available to them, many levels have multiple rewards. These can reward crafting materials, equipment, Pale Marks, or new features.

Progress for levelling Mercenaries is separated by realm (Eternal or Seasonal), but is otherwise shared across all characters on the same realm.

Bartering

When you have unlocked all four Mercenaries and invited them back to the Mercenary’s Den, Raheir’s adopted daughter will show up, unlocking a new feature called Bartering.

Bartering uses a dedicated currency called Pale Marks. As you level up your rapport with the various Mercenaries, it unlocks a greater number and variety of rewards to barter for. Rewards include legendary equipment and rings, gem fragments, master working crafting materials, boss summoning materials, and gold. The quality of the rewards available increases with the renown level.

Sources of Pale Marks were not well communicated through the UI. Other than the ones earned through the Renown track, I received Pale Marks in the rewards from Kurast Undercity, and they probably also drop from other end game activities such as the World Boss caches, and weekly cache from doing the new raid.