Complex sentence: The role of Solitaire is thus difficult for an Eldar to bear; only the strongest are able to endure the position and the knowledge that they will surely be consumed by Slaanesh upon death--those who are not strong enough either die or are driven insane.
Split into simpler sentences: The role of Solitaire is thus difficult for an Eldar to bear. Only the strongest are able to endure the position and the knowledge that they will surely be consumed by Slaanesh upon death--those who are not strong enough either die or are driven insane.