Iron Marines+: How to Defeat the Invasion Final Boss

To defeat the Invasion campaign final boss in Iron Marines+, dodge red ground telegraphs, clear summoned alien swarms away from your Ether extractors, and unleash high-burst damage on the boss's exposed core once its shields drop.

Recommended Squad and Hero Setup

Surviving the encounter requires balancing high mobility with durable frontline defense to withstand arena bombardment while bursting core phases.

Hero: Select a mobile hero equipped with burst damage or defensive barriers. High mobility allows you to dodge sudden area-of-effect (AoE) strikes and kite remaining threats if your frontline falls.
Frontline Anchors: Deploy heavily armored infantry or brawler mechas to absorb minion fire and intercept fast alien runners before they reach your defensive perimeter.
Ranged Attackers: Station high-tier snipers or rifle squads outside primary telegraph zones to maintain continuous fire on secondary targets and boss weak points.
Specialist Support: Maintain at least one splash-damage or crowd-control squad to wipe out dense clusters of low-health alien swarms along the arena edges.
Combat Drop Reserves: Stock consumable support items such as targeted orbital strikes, defensive energy shields, and repair drones to stabilize your units during phase transitions.

Phase Attack Patterns and Telegraph Responses

The boss encounter progresses through three escalating phases. Ground indicators expand in size and frequency as the fight continues, making squad repositioning your highest priority.

Phase	Primary Hazard	Threat Level	Required Player Response
Phase 1	Linear energy beams and targeted orbital shells	Moderate	Move squads laterally away from straight red firing lines and circular markers.
Phase 2	Sweeping shockwaves and dual spawn pods	High	Relocate ranged units to safe flanking positions; split forces to intercept converging minion waves.
Phase 3	Overlapping carpet bombing and enraged elite units	Critical	Keep your hero moving, sacrifice expendable units if needed, and burn the core with stored hero abilities.

During Phase 1, watch for red targeting outlines and circular indicators, ordering units perpendicular to firing paths immediately. In Phase 2, rotating hazards and lane-wide ground effects require shifting your squads between safe positions. In Phase 3, safe zones shrink significantly; keep your surviving units grouped tightly so a single movement command can relocate your entire force.

Defending Ether Extractors from Swarms

The boss periodically summons alien reinforcements through side portals to attack your forces and destroy your Ether harvesting infrastructure. Losing your Ether income halts unit replacement, resulting in a war of attrition you cannot sustain.

Secure Choke Points: Station automated turrets or durable frontline squads at paths leading from spawn portals to your Ether extractors.
Prioritize Lethal Adds: When spawn alerts trigger, redirect your hero and splash-damage squads to eliminate explosive crawlers and long-range acid spitters first.
Pin Basic Fodder: Allow frontline mechas to hold swarming runners in place while backline snipers clean them up.

Damaging the Exposed Core

Standard attacks cannot penetrate the boss while its invulnerable energy matrix is active. Save hero abilities, ultimate skills, and offensive consumables until auxiliary power pylons fall or a major attack sequence concludes.

When the core becomes exposed:

Trigger Hero Specials: Fire high-burst abilities and ultimate skills directly into the central core.
Focus Ranged Squads: Manually target snipers and heavy weapon units on the core, ignoring minor adds temporarily.
Deploy Offensive Drops: Place damage-amplifying combat items directly under your firing line.
Disengage Early: When approximately two seconds remain on the vulnerability window, pull your squads back toward safe perimeter lanes to avoid the boss's retaliatory knockback wave.

Emergency Recovery and Micro

If a squad takes heavy damage from an unexpected blast, pull the surviving members back to your base perimeter. Reinforcing a damaged squad costs significantly less Ether and time than training a new unit.

If your frontline collapses during the final phase, kite enemies with your hero along the outer arena perimeter. This pulls elite adds and boss targeting reticles away from your production base, giving your squad queues time to complete before you mount a final offensive push against the remaining core health.