The 3rd hero makes you powerfull. Asuming you're not using elemental mods it adds +11(?) damage, I know +11 looks quite weak, but remember you and your paras have 25% increased attack speed, that are alot of spears that hit the targets, the +11 suddently becomes quite strong, especially if you add melee henchmen too.
Dark Fury is imo less important, but it makes it easier for your heroes to spam their chants and shouts. (and for you, but you use focussed anger I asume?)
but if you use a derv for this, fc hero with for example tease for additional rupts, or maybe an minion master if you want some nice flesh shields (not needed with para defence, but why not they deal damage too.)
what I use with racway is usually the derv, but with earth prayers (they got buffed), but sometimes necro with machoism + aura of the lich (+3 death magic <3) and put 10+1 in blood and add dark fury and orders.
you can even use SoS ritualist with 10 (or more) in blood, loads of options. But orders makes the build strong, w/o orders, I wouldn't run racway.
look at all heroes (since you can adjust them) not just w/e works best in most situations. Yes the sabway minion master is good, but rac-way is no good w/o orders. (no offense to anyone) well these were my 2 cents, and I love to explain why I think so, any can disagree.