Board Thread:Warhammer 40k General Discussion/@comment-112.207.255.135-20161026083000/@comment-112.207.253.184-20161029234246

magnus try to warn the emperor but the emperor din't not listen to he ordered russ to arrest him not to kill him and his ready to arrest and the jugement of the emperor upon him

and here's the truth read it clearly

The Emperor saw Magnus as the traitor to the Imperium's ideals, not his beloved son Horus, whom he did not believe was capable of betraying him. Leman Russ ,  Primarch  of the  Space Wolves  Legion, who had always been averse to sorcery and had a general antipathy to Magnus as a result, was ordered to bring Magnus swiftly to Terra to account for his actions before the Emperor. During his voyage to  Prospero ,  Leman Russ  was instead ordered by an already corrupted  Horus  to destroy Magnus' Thousand Sons Legion rather than simply bring them to account. Horus, as the Imperial Warmaster, carried the authority of the Emperor Himself, and was therefore able to fool Russ into believing this was the Emperor's will as if the Emperor had thought about his decision and changed his mind. Accompanying the  Space Wolves  were a full contingent of  Adeptus Custodes, millions of  Imperial Army  troops, and the elite Imperial anti-psyker ( Pariah Gene -bearing) witch hunters known as the  Sisters of Silence.