If we want to talk optimal min/max, you have the WAR pull with NIN Shade Walker + early 3x FC (pre-Infuriate + RI @ 1s etc) so that Vengeance ticks hit the boss and WAR is in Deliverance asap.

Even more min/max, you just use 2 WARs.

Regardless, though, in a DRK/WAR comp you'd end up with more group DPS if you let the DRK take over after Berserk fades.