Hello, I have a question about dance of darkness.
Can the darkness effect from dance of darkness be heightened with the shadowdancer archetype ?
It's a focus spell, so heightens automatically at half your level rounded up. The darkness specifically says it creates darkness as the Darkness spell cast at equal level, so you don't have to do anything special to heighten the effect.
And since Dance of Darkness starts as a level 5 spell, it would be casting the level 5 version of Darkness to begin with. The heightened effect of Darkness happens at 4th level, so it is already there.