[The answer bubbles up out of Vincent before he can remark that it's not of Dante's business. It irritates him, but also he think of distinctly worse people he could possibly share this information with.]

Sephiroth did not know I existed until he arrived in Aldrip. However, I know him, and I knew his mother, who I loved.

I failed to protect her, and I failed to keep him out of the hands of a man who is sick with his scientific ambitions. As a result, the Shinra Company and Professor Hojo have been molding Sephiroth into little more than a weapon for them to command.

All because of my failure.