How Combat Works in Xterium — Rounds, Rate of Fire, Shields

On this page

The fight lasts a maximum of 10 rounds
Damage hits the shield first, then the armor
The shield partially regenerates between rounds
Rapid Fire: Bonus Shots ×1.5
The destruction of a ship is a probability, not “70% and an explosion”
What Turns to Rubble
How to Apply This
Frequently Asked Questions
What to Read Next

Combat in Xterium only appears to be a matter of “who has the bigger fleet.” In reality, it’s based on a straightforward system of rounds, damage types, and rate of fire. Let’s break it down step by step—all the numbers here are taken directly from the game’s code, with no guesswork involved.

Where do these numbers come from? All values in this article are taken from the game’s combat engine (combat calculation files). Explanations in plain language and tactical advice come from the player community (wiki, forum thread, authors Storm22073, Shataev, Kara). For a numerical summary of the ships, see the “Combat” section.

The fight lasts a maximum of 10 rounds

Each battle consists of up to 10 rounds. In each round, all ships and defenses on both sides fire once (plus any additional shots—see rapid fire below). If one side is destroyed before the round ends, the battle ends early.

An important implication: victory isn't always a "clean sweep." Over the course of 10 rounds, a weaker fleet may not have enough time to finish off the enemy, and some of the enemy's ships will escape. Therefore, it's not just the size of the fleet that matters, but also its composition.

Damage hits the shield first, then the armor

Each combat unit has three stats: attack, shield, and armor (hull strength). When a projectile hits a target:

First, the shield absorbs the damage. As long as the shield holds, the hull remains intact.
When there isn't enough shield, the remaining damage is absorbed by the armor (hull).
If the hull is breached, the ship could explode.

There’s a catch: if the damage from a single shot is less than a certain percentage of the target’s shield, it “bounces off” and doesn’t penetrate at all. That’s why many small ships have a hard time penetrating a heavy target with a large shield—their shots are simply absorbed. Conversely, heavy ships with a powerful salvo can penetrate the shield and deal damage to the hull.

The shield partially regenerates between rounds

This is often underestimated. Each ship type has a shield regeneration rate per round: for example, some ships regenerate 20% of their shields per round, while heavy ships can regenerate up to 30%. Between rounds, the shields partially “regrow.”

What this means in practice: It’s very difficult to break through a target with high shield regeneration using infrequent, weak hits—the shield has time to heal. You need a concentrated barrage that can break through the shield in a single round.

Rapid Fire: Bonus Shots ×1.5

"Rapid Fire" is the chance that a ship will fire again at the same target in the same round. Each ship has a table showing which targets it can use Rapid Fire against and with what strength.

In the game engine, the bonus shot multiplier is ×1.5. The more effective your fleet composition is against the enemy (the higher the rate of fire against their ships), the more shots you fire per round, and the greater your advantage. This is the “rock-paper-scissors” principle: the right composition against a specific enemy is far more effective than an equally “powerful” but poorly chosen composition.

The destruction of a ship is a probability, not “70% and an explosion”

In many similar games, a ship is destroyed if it takes more than 70% damage. Xterium works differently. Here, destruction is based on probability: the more damage a group of ships sustains, the higher the chance that ships within that group will start exploding. As damage accumulates, the “risk” of destruction increases, and losses accelerate.

Practical conclusion: Combat is nonlinear. A slight advantage with the right composition can turn into a rout in the final rounds, because damaged ships start falling like dominoes.

What Turns to Rubble

After the battle, part of what was destroyed turns into a field of debris above the planet:

50% of the resources from destroyed ships go into scrap;
Defense is not crumbling (0%).

A moon could form from the debris—for more details, see the separate article “Debris and the Chance of a Moon”].

How to Apply This

Composition is more important than size. Choose ships with high rate of fire when facing the enemy fleet—that’s more effective than simply having “more ships.”
You can't pierce the enemy's heavy shield with small arms—you need a concentrated volley.
Don't commit your fleet without a numerical advantage: combat is nonlinear, and losing often results in total destruction. For tips on how to defend yourself, see the guide “How Not to Lose Your Fleet”].

Frequently Asked Questions

How many rounds does a fight last in Xterium? A maximum of 10 rounds. If neither side is defeated after 10 rounds, the battle ends, and the survivors go their separate ways.

How does rapid-fire work in Xterium? Rapid Fire is a chance to fire an additional shot at the same target in the same round, with a damage multiplier of ×1.5. Each ship has its own set of targets against which Rapid Fire works.

How much does the shield regenerate between rounds? Depending on the ship type, this ranges from about 20% to 30% per round. Therefore, it's difficult to break through a target with a high shield using infrequent, weak hits.

How much of the destroyed fleet ends up as wreckage? 50% of the resources from destroyed ships are converted into a debris field. Destroyed debris defenses yield no resources (0%).