Upon completing the Rite of Rebirth, a dragonborn may choose to manifest the following aspect, instead of heart, mind, or wings.
Might (Ex): A dragonborn who selects the might aspect gains +2 strength, plus an additional +1 strength for each 5 HD the dragonborn posses, to a maximum of +6 strength at 20 HD.
At 6 HD and again at 15 HD, the dragonborn gains the powerful build special quality. If he already posses powerful build, he instead increases by one size category and loses the benefits of powerful build; the increase in size does not modify his ability scores.