Iron Marines+ Mission 6 Guide: How to Beat Diplomatic Incident

To beat Mission 6, Diplomatic Incident, on Sagan-1 in Iron Marines+, you must secure forward Ether nodes early, establish static defenses at natural chokepoints, and clear alien nests along the convoy route before activating the diplomatic escort. Diplomatic envoys have low health and cannot survive sustained enemy focus, requiring an active forward defense rather than turtling at your main base.

Securing Ether and Setting Early Chokepoints

Your starting command center generates minimal Ether, which cannot fund both unit production and static defense towers without expansion. Take control of resource points immediately upon landing.

Capture Forward Refineries: Move your starting combat squad outward right away to claim nearby Ether geysers before roaming Fell scouts harass your construction.
Erect Chokepoint Turrets: Place automated bullet or gatling turrets at ramps and narrow intersections. These provide steady anti-infantry damage against swift melee burrowers.
Manage Turret Health: Pull enemy aggression toward your hero when turret shields drop. Rebuilding destroyed turrets drains Ether and stalls troop production.

Recommended Unit Composition and Roles

Fell swarms combine fast melee burrowers, acidic ranged spitters, and heavy frontline bruisers. A balanced roster is required to prevent spitters from melting static defenses or swarms from bypassing ranged lines.

Unit Type	Combat Role	Recommended Positioning
Brawlers	Absorb aggro, hold choke lines, and stun heavy targets	Forward ramps and frontline intersections
Snipers	Eliminate acidic ranged spitters from beyond enemy reach	Elevated terrain or directly behind turrets
Assault Squads	Provide flexible mid-range damage and lane reinforcement	Central reserve between the north and east lanes
Engineers	Repair damaged defensive structures and shield towers	Stationed directly adjacent to active turrets

Pairing Brawlers with a resilient hero anchors the frontline and pins chargers in place. This allows Snipers behind your defensive perimeter to target corrosive spitters before they destroy static installations.

Protecting the Diplomatic Envoy

The mission fails if the diplomatic convoy is wiped out while moving toward the extraction zone. To ensure the VIPs reach safety, secure the path prior to transit:

Pre-Clear Ambush Sites: Do not trigger the escort phase while the travel route contains active Fell burrows or dormant egg clusters. Push an attack force through the designated path first to destroy hidden spawners and avoid two-front ambushes.
Form a Defensive Screen: Once the convoy starts moving along its fixed path, position your hero directly ahead of the escort's travel vector. Keep trailing squads close to protect the rear.
Peel Aggro Immediately: If burrowers emerge directly underneath the diplomatic units, immediately use hero crowd-control abilities, knockbacks, or localized strikes to redirect damage away from the VIPs.

Defending Against Late-Stage Swarms

The final phase triggers simultaneous assaults from both the northern and eastern quadrants. The northern path sends armored beasts, while the eastern path floods with fast swarmers.

Keep your Brawlers, a heavy turret, and your primary frontline anchor locked to the northern ramp to absorb heavy units. Station a gatling turret to slow the eastern swarms. Do not abandon the northern chokepoint when alarms sound for the eastern flank; instead, route your mobile Assault Squads and hero between lanes to intercept breaches. Hold your formation around the extraction perimeter until the evacuation counter reaches zero.