Every resurrection in the psychic laboratory was, in truth, a complex undertaking.
How difficult was it to resurrect a person?
Especially someone who had died tens of thousands of years ago.
The more powerful and complex a person was, the harder they were to resurrect.
Every resurrection required vast amounts of data calculation to reconstruct everything that had ever happened to them. Every particle had to be fully extrapolated. Having an intact body would have made things easier, but now they had only a skull.
Malcador could be resurrected at will because he had merely been drained to death by the power of the Golden Throne. Resurrecting someone who had been drained to death was simple.
But resurrecting someone who had fought their way out of a Chaos world required calculating an enormous amount of Warp-related data, data that was extraordinarily difficult to measure precisely. They needed to use time-based technology to trace it back and help them make accurate calculations.
Horus's resurrection was not actually the most difficult part. The real difficulty lay in calculating the consequences of resurrecting Horus, which was why they needed to reinforce the laboratory.
"Is this the skull?"
"Doesn't look like much."
"Don't stare at it. There's something wrong with this skull. It's connected to the Human Emperor's power."
The Emperor would grant a measure of his power. Through this binding, certain people could avoid being affected by Chaos. During the 30K era, Astropaths formed soul-bonds with the Emperor to avoid Warp corruption, allowing them to communicate within the Warp without being relentlessly harassed by daemons.
Gamma World was now using this power of the Emperor as an auxiliary tool, strengthening the stability of these souls and preventing both souls and flesh from being occupied by Chaos daemons.
Golden radiance flowed through the connectors.