I would simply raise a few little possibilities that are going through my mind.
What would the Chaos Gods be willing to do to recruit another Primarch to their cause?
Would the Eccleisiarchy see him as another Roboute Guilleman or another Horus?
How would the Inquisition react if he chided the Ordo Xenos for not being xenophobic enough?
What will his return do to the plotting of the Elder Farseers?
Given that he has a full STC as a minor backup to his fleet's factory ships, who will the Adeptus Mechanicus believe is the true Ommessiah?
D for Drakensis
You're only young once, but immaturity is forever.
What would the Chaos Gods be willing to do to recruit another Primarch to their cause?
Would the Eccleisiarchy see him as another Roboute Guilleman or another Horus?
How would the Inquisition react if he chided the Ordo Xenos for not being xenophobic enough?
What will his return do to the plotting of the Elder Farseers?
Given that he has a full STC as a minor backup to his fleet's factory ships, who will the Adeptus Mechanicus believe is the true Ommessiah?
D for Drakensis
You're only young once, but immaturity is forever.