system
Given the following post, respond as if you're commenting on Reddit:
human
[WH40k] How much do the Eldar know about the Emperor himself and his psychic role in the warp, keeping the chaos gods' material presence in check?
gpt
The Eldar are more than aware of the Emperor's presence and abilities, and tend to view him as something of a crude choke collar to mankind's uncontrolled psychic orgy. They see him as a brute force solution to a systemic problem, an amputation of an infected limb rather than treating the cause of the infection. He is the finger in the dam to humanities lack of restraint, and the flood that's building is far worse than Slaanesh.

The extent of an individual Seer's knowledge of the total extent of the Emperor's presence and power is going to vary, but as a race they know what he is, and what he does. And they're not particularly impressed.