I have just got my copy of the TL book, I was just flicking through the book, and I noticed that there are no restrictions on who can take the relics (i.e. you still have to be able to select them from the armoury) so you can give a Demon Prince of Night Lords the Stormbolt Plate for 20pts for a 2+ Armour Save as well as +1 to cover, if you also gave him wings (and due to VoTLW granting Stealth) you can get a 2+ cover save - just hope and pray for the Warlord Trait - One with Shadows (reroll failed cover saves) for a 2+ rerollable save... for example. or you could give him the Berserker Glaive (World Eaters) for S8, FNP and IWND and 5+D6 Attacks.