Shadowcasters and Domains, Rodent of Darkness help plz

[Avatar of the North]

Lets pretend for a moment that there is a class out there that out right adds a domain as known spells for any spellcaster (in spellbook for wizards & known spell list for spontaneous casters), How exactly would this interact with a shadowcaster. I think it would be knid of neat if they gained them as extra mysteries

 

[Archimedes314]

By RAW, no. The shadowcaster casts mysteries, not spells. But I'd let it work, the shadowcaster is horribly underpowered and thus could use any boost he can get.