User blog comment:XD1/Fan Brain: Marvel's Agents of S.H.I.E.L.D. - "Heavy is the Head"/@comment-1895174-20141004020943

Skye's father's connection to the Obelisk and the Obelisk's connection to the runes Coulson writes I guess means Skye's father is whatever the Guest-Host is.

Which would explain why Skye hasn't gone crazy the way Coulson has since she took that drug.