The Fires of Madness

I think that this is about as well as you can make Zarathur swarm at this stage. What I will note is that I think Void Pirates are better than Rogue Traders here. Although Ammo Depot provides great draw, everything you play is so cheap that the extra resources already pile up. Void Pirates and Ammo Depot allow you to go for heavy resource planets. These are planets that are sub-optimal in 90% of other decks, which prefer card draw, so you can rub your hands with glee as your opponent is forced either to allow you to rake in cash, or alternatively to be forced to commit command to what for them are stink planets.

Also, with no Splintered Path Acolytes you're a bit lacking in reliable 1 drops. Invektors are all well and good, but your opponent decides were they will go, not you. Although if you're having no problem with command, I can see the benefit of the Warbikers instead.

The only other change I would make is to drop Roghrax for another Plague Beast, or just drop it to get that sweet number 50. It all comes down to preference here, but for my part I have got to the stage where I would rather see anything else when I draw the Bloodhand.

One potential complaint that I can see is that without Noise Marines, and the Warblers instead, there are no juicy targets for Infernal Gateway - Roghrax being too expensive. However, I have found that I would much rather bring in a Flamer at the end of combat when the enemy is tapped out. After all, they end up doing 6 with Zarathur there, rather than the Noise Marine's 5, and with the tactical flexibility to divide this evenly between two targets. And having 4 makes this a more reliable combo than Noise Marines anyway.

But all this is just really good news for Zarathur, as it just shows that there are a wealth of great picks for him. And it's good for the game, because it means that no two Zarathur decks will be exactly alike.