"I'm a living time anomaly... My father was displaced, moving throughout time when he created me... The negative speed force connection just adds to it. ."

That's how him being erased from a timeline didn't affect me... That's how this Thawne is still kicking around.. Certain rules don't apply to me.. Even in flashpoint I would still be there somewhere..  Aware of everything,  the changes,  and immune to them..  I won't disappear into the nothing, into the Speed Force no matter who messes with the timeline.. I'll still be the Thad Thawne you know, or the one you don't know.. Even if there's a different version of Nora, or if my father tries to prevent my existence... I'll still be here.."