Vin-Tak: Asgardian, well that explains a lot.
Lady Sif: It is true, we do not trust Kree. That is why I am here. When Heimdall saw that one landed on your world, Odin charged me with retrieving him.
Vin-Tak: So you came to pick a fight.
Lady Sif: We know enough about Kree history to be concerned.
Vin-Tak: Well then if you know Kree history perhaps you've heard the tale of Terragenesis?
Lady Sif: Of course, ancient Kree descending on planets altering the inhabitants to fight their war.
Vin-Tak: And Earth was one of them.
Skye: Blue angels who fell from the sky.
Lady Sif: Eons ago the Kree waged a very long war. Casualties were high and they needed more soldiers.
Agent May: You mean cannon fodder.
Vin-Tak: We needed killers. One vicious faction among the Kree genetically modified other creatures' DNA. These modifications can be activated with Terrigen Crystals.
Lady Sif: We know these torturous experiments failed.
Vin-Tak: Not on Earth, here we had to shut them down. This faction had built a city. They brought with them the Diviners, which hold the crystals. Their plans were discovered and thwarted by the better of my kind. Putting an end to that dark chapter of our past.
Skye: Until now.