Guest-Host (Earth-199999)

"G.H." is the code-name given to a corpse used as part of Project T.A.H.I.T.I. and stored at the S.H.I.E.L.D. facility known as the "Guest House." The corpse was of unknown origin, estimated to be thousands of years old, and heavily scarred. It had lost the lower half of its body, making some of its organs visible, missing its eyes and part of its mouth, exposing some of its teeth. Bodily fluids extracted from the corpse resulted in the creation of a number of drugs, including the serum GH.325 which was instrumental in reviving S.H.I.E.L.D. agent Phil Coulson. However, Project T.A.H.I.T.I. test subjects subsequently suffered side effects ranging from aphasia to complete psychosis, compelled to write out a mysterious alien diagram. Dr. Goodman theorized that G.H.'s genetic memory was imprinting on the test subjects, creating a psychic schism. Coulson wanted to scrap the project and destroy the Host, but Goodman objected, believing that it was too valuable, and instead suggested rewriting the test subjects' memories to mitigate the effects.

Not long after his revival, Agent Coulson led a small team of S.H.I.E.L.D. agents into the facility, and found the vault marked as T.A.H.I.T.I. He investigated to uncover the source of the procedure used to resurrect him from death, and located a series of test tubes being filled by an unknown blue fluid coming from a chamber marked as "G.H." After opening the chamber, he saw that the source of the fluid was the corpse of a blue humanoid alien, being preserved in a stasis pod, leaving him incredibly disturbed.

The specimen was apparently destroyed when the bunker was blown up by the auto-destruction activated while Coulson's team infiltrated the Guest House to retrieve the GH.325 and use it to save Skye.^[1][2]

Coulson's team later learned that the Host was part of a rogue faction of Kree that came to Earth thousands of years ago to experiment on humans in order to create living weapons for the Kree Empire. They were responsible for the creation of an underground alien city for those "worthy" to be transformed by the Terrigen Crystals hidden in their Diviners, before their experiments were stopped by moderate Kree factions.^[3]

• The origins of the alien were not openly stated within the show until late in Season 2. Initially the Kree origin was hinted at, but only stated outside of the show by actress Chloe Bennet, later confirmed by Jeffrey Bell.
  • When asked about aliens with blue skin, Sif answered with a list of species including Interdites, Levians, Pheragots, Kree, Sarks, Centaurians and Frost Giants.^[4]
  • Jeffrey Bell stated that the alien was indeed Kree.^[5]