Ok, i know is little bit tricky to cast, and surely dangerous, but think about this...
Take Vampire lord, with lore of shadows, and flying, and 1 vamp, with that scroll that any double is iresistible.
Then, fly with lord on flank of enemy army, and cast pit of shades (with some luck, it will pass), then when you cast it, swap lord with vamp, and use scroll to cast purple sun.
After that, cast steed of shadows on vamp, to bring him back closer to units.
I know is highly unlikely to get all that, but if you manage, damage could be really big, and you will recover a lot of dices, so they will be able to cast some more damage on opponents
Take Vampire lord, with lore of shadows, and flying, and 1 vamp, with that scroll that any double is iresistible.
Then, fly with lord on flank of enemy army, and cast pit of shades (with some luck, it will pass), then when you cast it, swap lord with vamp, and use scroll to cast purple sun.
After that, cast steed of shadows on vamp, to bring him back closer to units.
I know is highly unlikely to get all that, but if you manage, damage could be really big, and you will recover a lot of dices, so they will be able to cast some more damage on opponents