Sugar Man

"Exposure to Cicero? ...I'll go."

Sugar Man (not named in game, but possibly the identity of The Old Man) is an enigmatic character seen throughout Mesa Black Research Center in all games within the Mesa Black Universe. He is only seen once by Clinically Silent Kalhun and the two protagonists of Half-Life and Treadmill, but can be seen monitoring the progress of Shephardt and Cicero, the latter of whom he eventually marries. His duty appears to be to ensure the quality of Mesa Black, though he later nukes it in Half-Life: Defense. As revealed in the aforementioned game, Sugar Man appears to be bilingual, and begins speaking an unknown language to Shephardt shortly before he departs him.

It's Half Life
"Suited for the hands of the public liberty. I have taken in a body, just leave the speech of MT Cicero. Many governments have to dress your opinion."

"I often thank you for checking out Zen."

"What have I done here, sir? Free."

"After more frustration... it just doesn't stop."

"It's not like a blanket. I have no regrets, Dr. Cicero."

Half Life: Defense
"So, the Shepherds finally got together."

"Hope you understand and apologize to you. I can't close report until I'm done with all my clothes. One of the most annoying things is the quality of the Black Mesa, but I think it will eventually take care of itself."

"No."

"I know I like people who can do everything."

"I hope you understand the importance adakalakalanin heart."

"No, it may not matter upidraficata you. Less well being, acquired."