Strength of Our Alliance requires three human players to coordinate a kill rather than relying on AI companions. The current completion route describes setting an enemy into the yellow critical state and having all three players participate in the group kill. Use a durable, isolated target, control damage carefully, and rotate hosting if only the host receives credit.
Party
Bring three human players—one controlling each fellowship hero—in the same AppID 2523770 online lobby.
Target
Choose a durable enemy without dangerous surrounding pressure so accidental attacks do not end the setup.
Critical state
Reduce the target into the visible yellow-critical opportunity, then stop uncontrolled companion or area damage.
Credit recovery
If only the host unlocks, change hosts and repeat the controlled action for the remaining accounts.
Build the correct three-player lobby
Legacy Edition officially supports online co-op for up to two friends, making a three-person fellowship. Have every player launch the Steam base game AppID 2523770 on the public branch. Match difficulty and confirm each person controls a distinct hero.
AI companions do not satisfy the human coordination requirement described by the current route. Local split-screen availability does not prove the same Steam achievement-credit behavior, so the documented setup uses online human participants.
Before choosing the target, run a normal fight and verify that all three players can attack, see prompts, and remain connected. Avoid attempting the unlock during a session already showing desynchronization.
Select a controllable enemy
Use an enemy durable enough to survive the setup but not a boss phase filled with ground effects or additions. Clear nearby opponents first. The group should have room to stand around the target and a safe recovery plan if its attack lands.
Remove damage-over-time effects, autonomous area skills, or excessive AI pressure from the setup. The target must reach the yellow critical state without dying to an uncontrolled tick. Equip weaker weapons temporarily if the group deletes ordinary enemies too quickly.
Agree on a stop call. Once the target is near the threshold, only the designated player continues until the visible critical opportunity appears.
Execute one synchronized critical kill
When the yellow state appears, bring all three human players into position. The current guide’s direction is that every participant should contribute to the group kill. Use clear voice timing—“ready, three, two, one”—and avoid a long animation that lands after the target is already dead.
The exact animation and prompt shown by the current game should guide the final input. Do not substitute an ordinary simultaneous attack if the critical opportunity is not active. A synchronized failure on the wrong state does not test the achievement.
After the enemy dies, stop and wait for Steam notifications. Each player should inspect their own achievement state rather than assuming the host’s popup represents the group.
Rotate hosting when credit is asymmetric
Current community evidence warns that only the host may unlock in some attempts. If that happens, preserve the successful procedure, return to a stable hub, and let another missing player create the next lobby. Repeat with the same three accounts and comparable target.
Record the first host, hero assignments, target, and who received credit. That log distinguishes host-sensitive behavior from a participant who missed the critical input. Continue rotating until every account has a controlled attempt as host if needed.
Do not edit achievement files, share saves, or mix AppID 32800 data. Normal host rotation stays inside the supported online session flow.
Troubleshoot a clean attempt with no unlock
Confirm there were three humans, the yellow-critical state was visible, all three participated in the finishing action, Steam was online, and the lobby used Legacy Edition. Check whether an area effect or companion delivered the actual final damage before the synchronized input.
Retry once with lower damage and a clearer target. If the result remains missing, capture video from the host and affected guest, plus lobby role and date, for Aspyr support. Community routing is evidence of a working method, not an official guarantee of identical client credit.
See Online Co-op for lobby preparation and Multiplayer Save Progress before changing hosts mid-campaign.