Dr. Zed Blanco is the first friendly human NPC that you meet in the game. Dr. Zed, like many other non-playable characters in this game, will give you quests. Dr. Zed spends most of his time in the infirmary in Fyrestone (and as you progress in the story, he'll move from Fyrestone to New Haven) where he chops dead corpses for reasons that are never explained. Dr. Zed also maintains the medical vending machines that you will come across throughout the world of Pandora.
He is also the Antagonist of The Zombie Island of Dr. Ned Under the guise of his "totally not made up brother" Dr. Ned. Although it is clearly the same person who changed the letter around