The Last Wall is a Black Library novel by David Annandale, the fourth in The Beast Arises series featuring the Imperial war against the Ork Warboss known as The Beast. It was published in March 2016.
As Terra itself comes under threat, the High Lords plan a last ditch attempt to defend the throneworld from the greenskin threat. Far away, the Iron Warriors fall victim to the Orks' expansion. And in the Phall system, the Sons of Dorn assemble to fulfill their Primarch's legacy.