Grow Empire: Rome: How to Unlock and Use Advanced Units

To unlock and deploy advanced units in Grow Empire: Rome, raise your city barracks levels and capture map colonies, then focus your initial gold on health and armor for one frontline unit and one ranged unit. Transitioning away from basic militia requires building around specialized combat roles rather than buying broad, low-level upgrades across every available branch.

Unit Roles and Combat Matchups

Advanced units in Grow Empire: Rome split into specialized archetypes designed to counter specific threats during defensive waves and colony invasions.

Unit Role	Examples	Primary Target	Tactical Function
Shock Infantry	Legionaries, Praetorians	Enemy melee infantry	Absorbs blunt strikes and uses shields against arrows to hold the line
Anti-Cavalry	Spearmen, Triarii	Barbarian cavalry, warlords	Applies passive damage multipliers to stop mounted charges at choke points
Ranged Specialists	Crossbowmen, Slingers	Armored cohorts, chieftains	Sacrifices fire rate to pierce heavy armor and destabilize shield guards
Mobile & Auxiliary	Cavalry, Tavern Mercenaries	Siege engines, archer lines	Flanks backline catapult crews or absorbs siege projectile fire

Deploying units without matching them to enemy archetypes leads to fast line collapses. Standard bowmen fire rapidly against unarmored tribesmen, but heavily armored Iberian troops or Roman rebel cohorts require slingers and crossbowmen to crack shield guards. Similarly, sending shock swordsmen into heavy cavalry rushes wastes gold, whereas spearmen stationed at the vanguard stop mounted momentum entirely.

Unlocking New Troops Through Barracks and Conquest

Accessing higher-tier units requires advancing both your city infrastructure and your regional territory:

Upgrade the City Barracks: Roman unit branch promotions are locked behind barracks building tiers and player level milestones. Reaching new tier thresholds permanently changes base troop behaviors and stats.
Conquer Campaign Colonies: Mercenary contracts and auxiliary units unlock as you conquer surrounding territories on the world map. Conquering these nodes yields tributary gold and unlocks regional options at the tavern, such as Gallic shock troops, Numidian horsemen, and heavy siege weapons.
Concentrate Early Investments: When a new tier unlocks, funnel your gold into a single frontline unit and one primary ranged unit. Upgrading four or five branches at once leaves your entire army under-leveled against escalating wave difficulty. Keep upgrading your chosen units until their base stats exceed the maxed stats of your previous-tier troops.

Recommended Army Composition

A balanced formation prevents bottlenecks and counters multi-wave compositions in both city defense and colony invasions:

Frontline Anchors (40–50%): A balanced split between Legionaries and Triarii spearmen to absorb charges, endure melee clashes, and protect the wall gate.
Ranged Damage Dealers (30–35%): Upgraded archers and armor-piercing crossbowmen positioned behind the frontline to eliminate advancing infantry and high-armor targets.
Mobile Shock Units (15–20%): Cavalry or tavern mercenaries held in reserve to flank enemy catapult crews or absorb incoming siege fire.

Spawn timing determines whether your composition succeeds. In defensive city waves, hold shock units until enemy vanguards make contact with your barricades, preventing your elite troops from taking free damage from long-range enemy volleys. In offensive colony invasions, deploy spearmen first to absorb initial defensive fire, then release cavalry to dismantle enemy siege lines and break backline formations.

Upgrade Priority Sequence

To maximize the return on your gold, prioritize troop survival before offensive output:

Unit Health and Armor: Increase defensive stats in the barracks menu first. High survivability keeps your formation intact, giving your wall archers, hero skills, and ballistas more time to clear waves.
Melee Damage and Attack Speed: Invest in offensive stats only after your frontline can survive standard wave durations without crumbling.
Fortress Defenses: Keep wall health and tower weaponry leveled alongside mobile troops. Elite field units function as an extension of your fortifications; neglecting wall-mounted ballistas and archer platforms leaves your army without sufficient fire support.