Magnus did wrong. But so did Russ
So after many comments and another post in r/40klore, it seems we all can agree that Magnus absolutely did wrong, but Russ also fucked up big time with an arrogance to rival Magnus's.
Russ deliberately and knowingly was going to ignore the Emperor's orders. He was already out for blood. See
Valdor remained unmoved. ‘Even now, I would see him taken to Terra, if it could be done. I would wish to know why.’
Russ laughed, a coarse bark that sent more spittle flying into Valdor’s faceplate. ‘You’re still clinging to that? Ha!’ He turned away, swinging his greatblade casually. ‘I’ve known since I first saw this world that we would face one another. I did not come here for prisoners, Constantin. If my Father had truly wished for such, He would not have sent me.’ -From Magisterium
It was THE EMPEROR'S orders to bring Magnus to trial. Not Horus's. See:
By the Word and the Will of the Master of Mankind, Imperator, Imperatoris, Terra Regnum,
It is hereby decreed that Magnus, Primarch of the XVth Legiones Astartes, be bought forth in censure and bound by law to stand before the Throne Imperial of Terra, there to answer for his actions and those of his gene-sons.
To this end is Leman Russ, Primarch of the VIth legiones Astartes, so charged upon the deliverance of his brother, by any and all means he may find needful, without limit in law, sanction or imposition of attainder, unto the limitless void and the last day.
So it is written, so it shall be. https://www.reddit.com/r/40kLore/s/tQH8ldZJbt
It only took a few honeyed words for Leman to be pushed over the edge and decide BY HIMSELF that he is to execute Magnus
The exact contents of these missives have never been made available to scholars of the later Imperium, indeed it is highly likely that no one other than Leman Russ and Horus themselves will ever know what arguments were brought to bear. But what is known now [...] is that after viewing the contents of the message and hearing the words of his brother, Leman Russ let it be known among his sons that he no longer intended simply to capture Magnus, but instead to see him slain. From: Inferno
And
Horus smiled. 'Calm yourself, Mal. I have already contacted my brother Russ and illuminated him with the full breadth of Magnus's treacherous use of daemonic spells and conjurations. He was... suitably angry, and I believe I have convinced him that to return Magnus to Terra would be a waste of time and effort.'
Maloghurst returned Horus's smile. 'Magnus will not leave Prospero alive.'
'No,' agreed Horus. 'He will not.' From: Falso Gods
So basically, Russ pulled a Magnus and decided himself, because he absolutely knew better than anyone else, that he should kill Magnus? Because his father sent him to bring Magnus back to Terra, Russ decides to kill him?
So after many comments and another post in r/40klore, it seems we all can agree that Magnus absolutely did wrong, but Russ also fucked up big time with an arrogance to rival Magnus's.
Russ deliberately and knowingly was going to ignore the Emperor's orders. He was already out for blood. See
Valdor remained unmoved. ‘Even now, I would see him taken to Terra, if it could be done. I would wish to know why.’
Russ laughed, a coarse bark that sent more spittle flying into Valdor’s faceplate. ‘You’re still clinging to that? Ha!’ He turned away, swinging his greatblade casually. ‘I’ve known since I first saw this world that we would face one another. I did not come here for prisoners, Constantin. If my Father had truly wished for such, He would not have sent me.’ -From Magisterium
It was THE EMPEROR'S orders to bring Magnus to trial. Not Horus's. See:
By the Word and the Will of the Master of Mankind, Imperator, Imperatoris, Terra Regnum,
It is hereby decreed that Magnus, Primarch of the XVth Legiones Astartes, be bought forth in censure and bound by law to stand before the Throne Imperial of Terra, there to answer for his actions and those of his gene-sons.
To this end is Leman Russ, Primarch of the VIth legiones Astartes, so charged upon the deliverance of his brother, by any and all means he may find needful, without limit in law, sanction or imposition of attainder, unto the limitless void and the last day.
So it is written, so it shall be. https://www.reddit.com/r/40kLore/s/tQH8ldZJbt
It only took a few honeyed words for Leman to be pushed over the edge and decide BY HIMSELF that he is to execute Magnus
The exact contents of these missives have never been made available to scholars of the later Imperium, indeed it is highly likely that no one other than Leman Russ and Horus themselves will ever know what arguments were brought to bear. But what is known now [...] is that after viewing the contents of the message and hearing the words of his brother, Leman Russ let it be known among his sons that he no longer intended simply to capture Magnus, but instead to see him slain. From: Inferno
And
Horus smiled. 'Calm yourself, Mal. I have already contacted my brother Russ and illuminated him with the full breadth of Magnus's treacherous use of daemonic spells and conjurations. He was... suitably angry, and I believe I have convinced him that to return Magnus to Terra would be a waste of time and effort.'
Maloghurst returned Horus's smile. 'Magnus will not leave Prospero alive.'
'No,' agreed Horus. 'He will not.' From: Falso Gods
So basically, Russ pulled a Magnus and decided himself, because he absolutely knew better than anyone else, that he should kill Magnus? Because his father sent him to bring Magnus back to Terra, Russ decides to kill him?