spell fpr umbral malady immune summons/undead

[unique arrow]

I am quite sick of my skelly boys and ghosts dying of Ubmral sickness once i befreing umbral dwellings.
Same with all summons.
I think that dwelling should sell spell to make summons immune too.
Like Umbral Binding - enchantment makes summons/undead immune to Umbral Malady

[proven flume]

already added