What difference does a battle model and a regular model of automatons have? The overall engineering? The protocols? Or is it something deeper? The answer was complex, and yet it was easy to explain using simple words. An iron dragon's scales were used to make the iron core isolator, within which a soul rests dormant until it is time for the host to take control of the inorganic organism.
Unlike regular automatons, the souls used in the battle model must belong to the living or at least a sane undead. For otherwise the protocols control the body, not a rational thinking person. Excising her heart and placing it in Avarice, Mono did the very same, and thus retained her memories and all of her past experiences, it didn't take long for her to master the flex of her new body.