"Necropolis" - changes to creatures of levels 6-7.

SRD, by default, Necromancy raises units from the Necropolis army. I don't know if this can be changed, but it would be better to make it so that it raises Death Knights, as it used to, along with dragons. Dragons should be made into powerful 8th-level neutral creatures, with one having a death blow ability and the other having incorporeality.