Reinforcements in LW2 follow specific rules that differ from vanilla XCom2 in several ways.
In LW2, the location of incoming ADVENT/Alien reinforcements is no longer denoted by a red flare (with the exception of Rookie difficulty where the flares are still present). Reinforcements will try to drop in locations where they can flank you and rarely drop out of view (but this can occur).
Any ADVENT or Alien unit can be part of a reinforcement pod. Alien pods will teleport rather than drop to the area. It's perfectly possible to have Chryssalid Hive Queens or Sectopods as part of the stronger reinforcements. Reinforcements will grow in stronger with each wave. They start slightly stronger than in vanilla and end much, much stronger.
Enemy reinforcements generally come at more or less regular intervals based on ADVENT Alert Level (strength) in the region. Some missions have higher Alert Level than others and this added Alert will affect reinforcements. LW uses a "reinforcement bucket" to control when reinforcements appear during a mission. It starts at 0 and start filling each turn even if your squad is in concealment(it is patched to reduce stealth mission). Each turn, a value based on Alert Level is added to the bucket. When the bucket reaches 1, a new wave of reinforcements will drop and the bucket is reduced by 1 (excess points above 1 will start filling the new bucket).
(for the mission)
|Bucket Increase per turn||Turns before reinforcements|
- On top of this, the Rapid Response Dark Event adds 0.1(Rookie), 0.15(Veteran) or 0.2(Commander+) to the bucket each turn.
- Reinforcements are slowed down globally by an additional value at Rookie (-0.25) and Veteran (-0.1).
- Some missions like Snare and some Retaliations use a modified bucket and will have faster reinforcements.
In every mission that's not either timed evac or "kill them all", strong 8 units reinforcements will start dropping each turn a number of turns after the squad breaks concealment and/or completes the mission objective. These "doom reinforcements" serve as a soft timer to force the player to eventually evac from the mission. The number of turns before doom reinforcements show up is based solely on the difficulty level.
Difficulty Turns until doom reinforcements start dropping After the squad breaks concealment After mission objectives are completed Rookie - - Vetetan 28 12 Commander 24 10 Legend 20 8