No Classes: All 6 Skill Trees Explained (4 Combat + 2 Exploration)

The Expanse: Osiris Reborn does not use character classes. You pick one specialization as a starting point, then spend skills across six trees — four combat trees (Marksmanship, Gadgets, Survivalist, Leader) and two exploration trees — while the weapons and gadgets you equip and upgrade do most of the work of defining how you fight.

The core idea: a classless, weapons-driven system

Owlcat states the philosophy in one sentence:

"Instead of choosing a fixed role, you develop your captain across four skill trees, but the weapons and gadgets you equip and upgrade ultimately define how you fight." — Owlcat, Steam announcement, 31 July 2026

That flips the usual RPG loop. Rather than a class telling you which gear to chase, your gear and the skills you mix are the build. The framing is player freedom — the announcement is titled "Weapons, Gadgets, and Player Freedom" — and the same post spells out what the skill trees do and don't do:

"Skill trees expand your captain's capabilities, but they don't determine your playstyle on their own. That comes from the weapons and gadgets you equip, the abilities they provide, and the upgrade paths you choose for them."

So the class is, in effect, a moving target rather than a locked decision — and your loadout is half the build.

What "specialization" and "Starting Class" actually mean

The announcement's Steam page subtitle is "How your gear, not your class, defines the way you fight," and the body explains that the opening choice is a foundation, not a lock-in:

"At the start of the game, you'll pick a specialization that sets your captain's initial skills and gear. For example, a cyber warfare specialist (formerly a hacker in the Beta) starts the game with decent gadget expertise, and their playstyle leans toward using abilities more than firearms. A firearms specialist (formerly an officer) starts with better shooting and leadership skills, relying both on their own aim and on issuing orders to companions in combat." — Owlcat, Steam announcement, 31 July 2026

Two starting specializations are named so far: the cyber warfare specialist (called "hacker" in the beta) and the firearms specialist (called "officer" in the beta). The full list has not been published, so treat these two as examples rather than the complete roster.

The four combat skill trees

Owlcat's beta guide counts "4 combat skill trees, 2 exploration skill trees, and 1 perk they get from their origin" — six trees total. The dev blog names the four combat trees and defines each one at the tree level:

Skill tree	Owlcat's definition (verbatim)
Marksmanship	"The marksmanship skill tree focuses on your mastery of various weapons and unlocks bonuses to critical damage, accuracy, and other combat modifiers."
Gadgets	"The gadgets skill tree focuses on making your gadget-related abilities more powerful, increasing damage and duration, reducing the cooldown of abilities, etc."
Survivalist	"The survivalist skills, as the name suggests, ensure your survival in combat by increasing your health, armor, armor regeneration capabilities, as well as providing unique bonuses that make you more lethal to your enemies while you are exposed or engage in melee."
Leader	"The leader skill tree represents your ability to work with your crew. It provides various bonuses to your companions, such as weapon and ability damage, increased armor and damage reduction, and buffs for your own captain while companions are nearby."

Crucially, all four combat trees stay open to every character:

"Specializations don't restrict your progression or lock you into a particular role. You can begin as a cyber warfare specialist, invest in weapon skills as you level up, and gradually turn your captain into a hybrid of a cyber warfare and firearms specialist. All four combat skill trees — Marksmanship, Gadgets, Survivalist, and Leader — remain open, so you are free to combine them and develop your captain in the direction that suits you." — Owlcat, Steam announcement, 31 July 2026

Tree-level scope is fully published; the point-by-point breakdown inside each tree is not, and neither are the two exploration trees' names or perks.

The two exploration trees

The beta guide counts two exploration skill trees alongside the four combat trees, but Owlcat has not named them or described their perks in any announcement we've seen. They're counted, not detailed — so this page won't invent names or perks for them.

The same guide's "1 perk they get from their origin" is already concrete:

"For example, a Belter gets a Tekimang perk that adds +1 to all Engineering checks, and an Earther gets the Gravity's Gift perk that adds +1 to Athletics checks." — Owlcat, Steam announcement, April 2026

Put the count together and you get the six-tree picture — four combat trees (named and defined above), two exploration trees (counted but unnamed), and the origin perk — all sitting on the classless, gear-driven foundation. The skill trees are only part of it: as the announcement puts it, they "expand your captain's capabilities, but they don't determine your playstyle on their own."

How progression actually works

The loop, step by step:

Pick one specialization at character creation — it "sets your captain's initial skills and gear," nothing more.
Level up and spend skills freely across the four combat trees, mixing Marksmanship with Survivalist or Leader with Gadgets.
Equip and upgrade weapons and gadgets — these "ultimately define how you fight."
Refine at the workbench, where each upgrade choice pushes your gear toward a playstyle.

On respeccing, the announcement is direct:

"Mix and match as you like — you won't be able to take everything, but nothing stops you from leaning into two directions at once. Change your mind later, and you can respec on your ship for a price (increases each time)." — Owlcat, Steam announcement, 31 July 2026

Weapons and gadgets are the other half of your build

Because there are no classes, gear carries a lot of the build weight:

Every weapon type is available to everyone. "In The Expanse: Osiris Reborn, any character can fight with any weapon they like. There are 5 classes of firearms you can find:

Assault Rifles

Shotguns

Pistols

Submachine guns

Sniper rifles" — Owlcat, Steam announcement, April 2026.

Upgrades come in three broad kinds, in Owlcat's words: "Some upgrades are straightforward stat boosts: more damage, a wider radius, a shorter cooldown. Others are triggered effects, like a damage bonus that stacks with every kill. And a few rarer upgrades can unlock entirely new abilities for your gear."
Workbench upgrades are an exclusive choice at each tier: "At each tier, you'll make an exclusive choice between two or three upgrade paths, pushing your gear toward your desired playstyle, until reaching the final tier, where the item can be upgraded with a powerful final perk."
Quality caps upgrade depth: "How far you can take an item depends on its quality. While you can't upgrade quality directly, you can find a higher-quality variation of the same weapon or gadget, which allows you to unlock further upgrade depth that the original item lacked."

This is the part that makes two players with the same specialization feel different: same starting point, completely different gear choices.

How this changes how you think about builds

Don't hoard "respec anxiety." You can respec on your ship, so early picks are lower stakes than they look — but the price "increases each time," so it's not free to change constantly.
Gear first, then skills. Since weapons and gadgets define combat, it's often smarter to build around a weapon you love than to force a weapon into a pre-planned role.
Experiment as you find things. The system is explicitly built so your playstyle can change when you find a new gadget or a rare upgrade.
Think in lanes, not classes. The combat trees are complementary lanes rather than rival roles — the interesting builds come from spanning them.

Companions have their own trees too

The classless system extends to your squad:

"Building your crew is also part of building your playstyle. Your companions also have skill trees, and their signature gadgets also have their own unique upgrade paths, allowing you to tailor their combat roles to your captain's strengths and weaknesses." — Owlcat, Steam announcement, 31 July 2026

Owlcat's example is Zafar: "Take Zafar, for example, an engineer who joins your team early in the game. With no upgrades, he installs a portable turret to hold a position. From there, how the turret evolves is entirely up to you." So a companion stays in their field — but how they grow inside it is your call.

What we still don't know

A full per-node list for each combat tree (tree-level definitions are published; the point-by-point breakdown is not).
The two exploration trees' names and perks.
The complete list of starting specializations (two are named; the rest aren't).
Whether any tree is exclusive to the player character (not stated in any announcement we've seen).
Exact upgrade costs and the respec price (only "for a price (increases each time)" is stated).

FAQ

Are there classes in Osiris Reborn?

No. It's classless — you pick a starting specialization, then mix skills across four combat trees (Marksmanship, Gadgets, Survivalist, Leader) and two exploration trees.

What do the four combat trees do?

In Owlcat's own words: Marksmanship "focuses on your mastery of various weapons and unlocks bonuses to critical damage, accuracy, and other combat modifiers." Gadgets "focuses on making your gadget-related abilities more powerful, increasing damage and duration, reducing the cooldown of abilities." Survivalist "ensure your survival in combat by increasing your health, armor, armor regeneration capabilities, as well as providing unique bonuses that make you more lethal to your enemies while you are exposed or engage in melee." Leader "provides various bonuses to your companions, such as weapon and ability damage, increased armor and damage reduction, and buffs for your own captain while companions are nearby."

Can I change my build later?

Yes — you can respec on your ship, though the price "increases each time." See the respec guide for the mechanics.

Do companions use the same skill trees?

They have their own trees and signature-gadget upgrade paths, letting you tailor their combat roles to your captain's strengths — but they stay within their field of expertise.

The sources behind this guide

All quoted lines in this article are copied verbatim from Owlcat's Steam announcements: "Weapons, Gadgets, and Player Freedom" (31 July 2026, app 3727390) and "Quick Guide to the Beta" (April 2026). The verbatim text was transcribed by the content reviewer from the Steam news API; we could not open the Steam announcement pages or RSS feed directly this session. The full quote-by-quote trail is in the evidence file.

Last updated: 2026-11-12. Unofficial fan site — The Expanse is an Alcon/Syfy property.