Some spells like Summon Earth Elemental allows me to select the caster in case I have several units that are able to cast it.
The unlockable spell Touch of Darkness (empire only) has no such selection. Instead, it will simply be cast by the first character in the list (most likely your sovereign). There is no indication that this spell will be cast on that unit when you use it. We should be able to select who gets to cast it.
