Potent Ancestry (3.5e Feat)
From D&D Wiki
Potent Ancestry [General]
While some only manifest their ancestry in small ways something has made them surface more strongly in you.
Benefit: Gain an Intermediate or Major Bloodline
Normal: Must take several feats to reach more powerful bloodlines
Special: Must provide a reason why this bloodline has manifested to the DM, be this through backstory or recent game events.