The meaning of the fragment is clear. I'll get to that in a moment. First, let's see if we can agree that the text in red in the first post is not a sentence. It lacks a verb. It looks like a long adjectival phrase in which the writer describes himself or herself.
Though more than a bit like = I am, however, something of...
a manipulative bastard in my own right = a controlling and despicable person myself.
This appears to be a comparison the writer makes to the recipient of the note she or he has sent or is sending. The sense of it is that the person on the receiving end is a "manipulative bastard", and that the writer shares that characteristic to more than a small degree.