Non. La création d'un Hero n'implique pas le ralliement du MMC.
A15.21 : "A MMC which creates a hero is not affected in any way (other than possibly also increasing in value due to Battle Hardening)."
C'est le Battle Hardening qui permet un ralliement :
A15.3 : "This Battle Hardening effect improves the unit in Class (even if broken) by exchanging it for an unbroken, unpinned unit of the same size but the next higher quality. "
Maintenant, il peut arriver qu'un Hero creation coïncide avec un Battle Hardening...