Infantry Conversion
The people of the Red Ocean learned pretty soon that giving Carmine mechs to completely untrained civilians was a big waste.
It was not impossible to train them into effective combatants, but the time it took to instill so many essential fighting skills and theories was so long that the Red War might already be over by the time these folks could prove themselves on the battlefield.
Clever people quickly realized that by prioritizing existing infantry soldiers, they could not only shave valuable years off that lengthy training period, but also gain a large amount of obedient and disciplined Carmine mech pilots!
More importantly than that, these pilots might not all be blooded, but their prior training should have already hardened them for warfare. This meant that they were much less likely to lose their morale and trigger a premature rout.