How to Defeat Hostail's Bosses in Xterium

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Step 1. Understand who the Hostile bosses are
Step 2. Go through the sectors in order
Step 3. Assemble a fleet to take on the boss
Step 4. Assemble the cores and reactors
Step 5. Unlock additional arsenal slots
Step 6. Don't lose your fleet when fighting bosses
Common Mistakes
Frequently Asked Questions
What to Read Next

Hostail bosses are the main source of cores for the [](/knowledge/encyclopedia/arsenal) arsenal, the most valuable component for upgrading your fleet. But these bosses are much stronger than regular enemy locations, and attacking them unprepared means losing your fleet. Below is a step-by-step guide on how to defeat Hostail bosses: what kind of fleet you need, the order in which to tackle the sectors, and what loot they drop.

Where did this guide come from? The names of sectors, enemies, cores, and parts, as well as the unlock order and access requirements, are taken from the game’s code (expedition and arsenal files). The strategy for assembling a fleet to take on bosses was described by the player community (player wiki, forum thread, authors: Storm22073, Shatayev, Kara). The combat statistics have been verified against the section How Combat Works.

Step 1. Understand who the Hostile bosses are

"Hostile" is [](/knowledge/encyclopedia/expedition) an expedition into a dangerous sector where four types of enemies await you, in ascending order of strength: Ruins → Barbarians → Pirates → Devastators ("Ops"). Each sector has 50 checkpoints, and every tenth checkpoint (10, 20, 30, 40, 50) features a boss: it’s significantly stronger than regular checkpoints, but the reward is also more valuable. Bosses drop cores that aren’t available at regular checkpoints.

Step 2. Go through the sectors in order

The sectors unlock in order of increasing difficulty, and to advance to the next one, you must upgrade Hostail's technology level and earn victories at the previous checkpoints:

The ruins are the weakest area; always start there;
Barbarians — unlocked after upgrading the Hostile technology;
Pirates—require an even higher level of technology;
The Devastators are the strongest sector; they are unlocked last and yield the most valuable cores.

Don't jump into a high-intensity sector before you're ready—each subsequent sector requires significantly more fleet strength than the previous one.

Step 3. Assemble a fleet to take on the boss

A boss isn’t just a single ship—it’s an entire defensive group—and it deals more damage than a regular enemy. The composition of your fleet is what matters here, not just its size: the battle lasts a maximum of 10 rounds, and you must defeat the boss within that time. Experienced players assemble a mixed fleet for bosses, including heavy ships (which can penetrate the boss’s powerful shield) and ensure their fleet’s firepower significantly exceeds that of a standard target of the same level. A “close-range” assault on the boss is a common cause of fleet loss.

Step 4. Assemble the cores and reactors

Most of Hostail's loot goes to the [](/knowledge/encyclopedia/arsenal) arsenal:

Standard nodes provide components—Control Module, Distributor, Reactor, Capacitor, Storage Unit, and others. Each sector has its own set of components.
Bosses drop cores—the most valuable item. Each sector drops its own core: Barbarians drop a Class I Core, Pirates drop a Class II Core, and Ravagers drop a Class III Core. The deeper the boss’s location (10 → 50), the higher the chance of getting a core.

These parts and cores strengthen your fleet and defenses through the arsenal—for instructions on how to equip them, see the guide How to Upgrade the Arsenal.

Step 5. Unlock additional arsenal slots

Hostile isn't just about the cores. When you reach the maximum Level 5 enemy in Hostile, 3 additional upgrade slots become available in your arsenal (in addition to the 8 main ones). This is yet another reason to level up sectors all the way through, rather than stopping at the easy spots.

Step 6. Don't lose your fleet when fighting bosses

A boss takes out more ships than a regular point, so the risk of losses is higher. Before raiding a boss, make sure you have more than enough forces, and don’t take on a sector boss that’s beyond your current capabilities. It’s better to safely farm regular points and stockpile parts than to lose your entire fleet to a boss. General rules for fleet survival can be found in the guide How Not to Lose Your Fleet.

Common Mistakes

A "close-range" raid on the boss. The boss is stronger than a regular enemy—without enough firepower, you could easily lose your fleet.
Jump to a strong sector. The Ravagers will wipe out the fleet if they're not prepared. Go to Ruins → Barbarians → Pirates → Ravagers.
Only easy targets. Unless you reach the enemy's 5th level, additional arsenal slots will not unlock.
A small fleet against the boss. A lot of weak ships don't do much damage to the boss's shield—you need a fleet with heavy ships.

Frequently Asked Questions

Who are the bosses of Hostail? Each of the four sectors in Hostail (Ruins, Barbarians, Pirates, Ravagers) has 50 points, and every tenth point (10, 20, 30, 40, 50) is a boss. A boss is stronger than a regular checkpoint but offers a valuable reward—an arsenal core.

What do Hostail bosses drop? Cores for the arsenal: Barbarians drop Class I Cores, Pirates drop Class II Cores, and Devastators drop Class III Cores. The deeper the boss location, the higher the chance of obtaining a core. Regular locations yield components (modules, reactors, distributors).

In what order should I go through the sectors? In order of increasing strength: Ruins → Barbarians → Pirates → Ravagers. Each subsequent sector unlocks after upgrading the Hostail technology and requires more fleet strength.

What kind of fleet do you need for the bosses? A mixed fleet consisting of heavy ships capable of breaking through the boss’s powerful shield, with more firepower than usual. The battle lasts up to 10 rounds—during this time, the fleet must defeat the boss.