Requires 4 kills to activate.
Rapid Regen rapidly heals all allied heroes on the battlefield for 8 seconds. They gain a green glowing aura and begin emitting green cross symbols for the killstreak's duration.
Mayday, the unique Medic, uses this Killstreak.
- In the mission Doctors of Doom, all of the enemy Medics are constantly affected by permanent Rapid Regen. This mission is also where the Medic class is unlocked.
- Rapid Regen also appears as a Killstreak in Strike Force Heroes 1 and 2. In the first game, it was used by Medics. In the second game, it was used by Generals.
- In the final mission, Devs De La Muerte, Rapid Regen is the third Killstreak used by Justin and Mike. It is also used in Justin and Mike's true forms when they use all their previously used Killstreaks combined.