Sanguinius against Horus (Vengeful Spirit)

Teleporting aboard the Vengeful Spirit together with the Emperor and Dorn, Sanguinius found himself cut off and was the first to meet Horus, brimming with the power of all four gods of Chaos. The Warmaster offered his brother a last chance to renounce the Emperor — the Angel of Baal refused, and Horus easily strangled him. The death of Sanguinius, who had not retreated before the omnipotence of Chaos, gave rise to the Black Rage in his sons.