What do you call a person who lies vehemently for deceitful and selfish reasons, and will shamelessly defend it no matter what?

Pathological liars lie constantly with no rationale or motive behind it. It's kind of like a psychological problem they have. But I am not talking about pathological liars.

What do you call someone who lies in order to get something he wants, or to deny any wrongdoing? And this person will defend his lie at all costs, no matter what, even to the point that he would rather have you apologize back to him for questioning his lie and he would not feel the least bit bad about it as long as his lie held up. This person is so shameless that even if he knew that you knew he was lying, he would still look at you straight faced and still lie right through his teeth. This person would not care one bit to throw you or someone else under the bus in order to uphold his lie. I am talking about a real piece of shlt here. If upholding his lie meant someone would die as a result, he would STILL lie. That is how selfish and messed up this person is. He simply doesn't care about anything but himself, and he will lie at all costs to get what he wants.

What type of liar is that person? Is there an official name for it?