This guide will let you know how to unlock the Legacy campaign (16 Secret Units) in Totally Accurate Battle Simulator.
You will need to find all secret units in the legacy map to unlock the Legacy campaign.
Open Legacy Map
The first thing you have to do is open the Legacy map in sandbox mode.
And click F to enable the free cam mode.
Super Boxer
Blow Dart (Blowdarter)
Poacher
Pike(men)
Dark Peasant
Pharaoh
Super Peasant
Thor
Tank
Wizard
Chariot
Banner Bearer
Boxer
Barrel Roller
Flag Bearer
You can find these units in the legacy faction sector.