#but i cant imagine him super eager to believe Szarekh at least at first

[ghostinthegallery]

Szarekh should taunt Roboute with his sangunius death mask and possible memories of him. Kick him while he's mentally down, reminding him of his dead brother he liked.

Please, that is far too simple (and paints Szarekh as a one-dimensional villain, which I do not think is the direction GW should go even if they probably will). No, no, we can make this set up so much worse.

Szarekh appears in his death mask of Sanguinius, claiming to have known him. He shares memories of him. He may not speak directly, but he shares his experiences with Sanguinius the best way he can.

And Guilliman is furious. How dare this alien bastard tell such an obvious lie? How dare he blaspheme, disrespect the memory of someone Guilliman loved and respected? His brother! Because it can't be true. Sanguinius would never have had a relationship with this soulless monstrosity. It goes against everything their father wanted and created them to do. Yes, Guilliman hates what the Imperium has become, but he is still fundamentally of it. He was made to purge anything not human (and a very specific kind of human at that.) He has worked with aeldar, wure, but this is different. This is too much. He's never going to trust a word the Silent King says (or implies given the whole "silent" thing.)

So Guilliman throws his forces into the meat grinder. The wall of a technologically superior force. He fights this wad, and maybe his anger and grief makes him just a little less stable. A tiny bit less measured. The slightest, slightest bit more aggressive.

And people die. Lots of people die, but they are perfectly happy to because that is what their god and his living son ask of them. They are avenging the name of their Angel, that the filthy xenos dared to disrespect.

But...what if Szarekh is, in fact, completely genuine when he says he knew Sanguinius? That they met, were willing to work together, were...friendly? Friends? More than friends? And Guilliman, far into the campaign, finds irrefutable proof that this is true? Sanguinius wanted this alliance. Szarekh wanted it too, and was willing to have it with Guilliman too. There was a peaceful way forward for the two leaders, if Guilliman had only listened? He could have made the universe just a tiny bit safer for humanity, just a tiny bit brighter.

And he failed. He chose his father's hatred and his own distrust. He was wrong.

What then? Does he accept that he made a mistake? A mistake that proves Sanguinius was willing to commit the worst heresies? Does he still see his brother the same way after that? Does he try to correct his grievous error and honor Sanguinius, despite all it would cost him? If it is even possible? Can Guilliman shift his worldview that much that quickly?

Or does he deny it? Does he choose the comfortable lie, that Szarekh is the enemy and is just using Sanguinius' face to insult him? Does he surrender a little bit more to the dogma consuming his father's empire? Everyone around Guilliman will tell him this is the correct choice. He'll be praised, lauded. Worshipped for his strength of will. And maybe it's a necessary sacrifice, in his mind. The Imperium would tear itself apart if he tried to ally with a xenos. He has to keep the machine going. Doesn't he? Nobody will ever know...

What's the Avenging Son to do?