Die-Hardman, real name John Blake McClane is the current & 3rd President of the United Cities of America and Director of Bridges. Die-Hardman was originally a member of the green beret under the command of Captain Cliff Unger. Some time after Amelie is captured by the Homo demens, Die-Hardman works with her to attempt to convince Sam to continue on her westward expedition, connect all cities to the Chiral Network, and bring her back to Capital Knot City.

Die-Hardman's mask has text on its forehead that reads "BR-10-14P-9999 LUDENS". The mask's jaw moves with his own jaw when he talks. Deadman asks Sam why he wears the mask since he knew him by long date, which he replies that when he first met him he was already wearing a mask being told that it had something to do with burns to his face.

It is later revealed that his face is not damaged, and he is using it to hide his face.

Source: https://deathstranding.fandom.com/wiki/Die-Hardman