you had amnesia from a huge concrete falling on top of you (somehow, you survived). You don't remember anything or anyone but this one person. Your "worst enemy". Tartaglia.

though you didn't know he was your enemy from the amnesia, you had this indescribable feeling towards him, that's how you 'remembered' him

"So you don't know anything about me, but have this..'feeling' that you know me that doesn't happen to any of your family and friends?" tartaglia asked,an amused smirk on his face