Play a bunch against daemons, not so much against VC. Obviously a light slann would work well. Also, be sure to bring a banner of flame if you can.
For tactics, as a general rule, I will move up on the sides, and hang back in the middle with the combat blocks. You generally want to get rid of the chaff and units on the flanks, and cast spells at the main blocks for a long as possible. And if you take skink priests, go with heavens. Good for taking out the flyers.
I've found that 42 Saurus Warriors with spears joined by a Scar-Vet BSB carrying a halberd does wonderful things. I don't even put this unit in a horde formation either, I run a 7x6 block with full command. I haven't played against Demons, but I play against VC a lot. As long as you have a solid block of Saurus (or Horde) and a character, you are guaranteed to counter the VC's "Blender" tactic. I typically run with 12-14 skink skirmishers to act as a screen in front and/or to protect flanks. I will also take a Salamander to be a flank protector. Even without Lore of Light, you can still do amazingly against VC with any other lore. Last game I took Wandering Deliberations and since I was more combat focused, I won with very little magic on my side.
A forum community dedicated to Wargamers, Wargaming 40K enthusiasts. Come join the discussion about Warhammer and Wargaming collections, miniatures, tactics, terrain, reviews, accessories, history, displays, models, styles, scales, reviews, accessories, classifieds, and more!