two blonde bombshells :3

Blades do have DNA recorded within them, and while the Trinity Processor cores are different from standard core crystals, they are made with biocomputer elements and manage the information sent to them from blades, sending back evolutionary data (aka DNA). So Mythra should have a bunch of DNA recorded within her, even if she's just physically made up of technology and ether (though they never dive too deep into how blade biology actually works).