Here's another oldie I never had a topic for. Undead Summoning brings back the old art of summoning up Undead like we could do back in Oblivion and Morrowind. You can summon Skeletons, Corrupted Shades, Draugr, Draugr Lords, and Dragon Priests.
The Summoner, Necromancy and Twin Souls perks work with Undead Summoning. However, I could not get the Dark Souls perk to work with the undead you can summon. I believe this is due to the differences in the game engine between summoning and reanimating. So that you do not have to take the Dark Souls perk just to get to Twin Souls, I have created a second perk called Twin Summons that does the same thing, requiring only Necromancy, and of course a Conjuration skill of 100.