7th Ed. need help with undead

[Caneghem]

I knew flaming affected tomb kings but thought it didn't affect vampire counts, which uniters are hurt by fire?

The Tomb Kings are flammable, so flaming doubles wounds against them.

Vampires have regeneration, so flaming is good against them because it stops regen saves. Vampires also have a banner that gives regen to whole units, as well as various other nasties that have regen.