Is there any lore out there for Kalitas of Ghet?

Yes
What it boils down to is that there was a prior bloodchief of House Ghet, Tenihas. He had a well-archived history of the vampires, including bits about their Eldrazi-tied origins, but would not allow Anowon or anyone else to study them.

Bloodchief Tenihas ends up dead and Anowon has abandoned House Ghet. One "surviving witness" says Anowon had killed Tenihas. We do not know if Kalitas was the witness, but Kalitas soon fills the position as bloodchief of Ghet regardless. So now Kalitas has access to the ancient texts, learns the vampire history, and has the leadership of the entire poor district of Malakir. Woohoo!

Now, we see Kalitas has defected to the Eldrazi side of battle, along with most of his Ghet vampire family. He likely shared the secrets of their origins, twisted or not, with his entire house so they would join his oddly-aligned fight for survival. Kalitas lead a failed attack on Malakir, hoping to turn all other vampires of the city into Eldrazi thralls like himself. Drana kicked him out of the city and that is the last we have heard of him in BFZ.

The interesting questions is whether Kalitas actually killed Tenihas. We've seen Anowon kill random Zendikari for a chance at getting closer to his goals, but killing direct family for exile and some origin history seems strange. We will likely never get resolution, but it's safe to say the whole of House Ghet would not be aligned with the Eldrazi now were it not for Kalitas rising to power.