Pieter Burke is the Belltower commander and is the main antagonist of the Deus Ex: Human Revolution DLC addon The Missing Link.
Burke was a sexist US marine officer who was dishonorably discharged, however, the specifics of his backstory are especially redacted. He also was close acquaintances with the Tyrants.
The Missing Link
Afterwards, Burke found and interrogated the cybernetic spy Adam Jensen on a Hei Zhen Zhu cargo ship. However, Jensen escaped and took down most of Burke's army before confronting the commander himself. It is player dependent whether or not Burke lives, as Jensen could kill or spare him after defeating him.