[@Prince Potter] Ok, I'll fill you in

So basically, the Emperor and several of his Primarch are fighting the Ullanor crusade against the ork Warlord and his WAAAAAAAAGH! there. The Emperor and his Zodiacs have dispatched the Warlord and sent a call to all Primarchs to come to Ullanor, in order to attend an as yet undiscussed council.

As for individual Primarchs, the First Son Mon-Kal is now on his way to Ullanor after being heavily wounded in a duel with the Eldar Avatar of Khaine on Craftworld Ibrayesil.

Most all the other active Primarchs are at Ullanor I believe, dealing with the Ork Waaaaaagh! in the sector before coming to Ullanor proper.

Thats about it so far so... feel free to jump right in! Please PM me and the GM with any questions.

If you want help or advice on your primarch, feel free to PM one or both of us. And, of course, PM your finalized sheet to both of us for approval