[@VitaVitaAR][@Wraithblade6]

Daemon don't have 'souls' in the normal sense. Specifically Magnus' 'Soul' has been removed by Tzeentch, and then replaced with a large blob of Warp Energy. Warp Energy being raw psychic/emotional energy, comparable to the Force if the Force hated you. This is also the same raw building material as 'souls' in the 40K universe, however. And the body of Daemons is also composed of basically solidified Warp-stuff, which is again the raw building material for 'souls'.

So yeah, it's up for debate, but you two should probably agree on whether Hakuroken affects Magnus.