Really deadly. I like it! Shadoblade + assassins is highly efficient. Doomfire Warlocks are far morescarier than Ogre's maw. And Hellebron + Executioners can wipe away entire units. Plus, if you're using Hellebron, you already have the command ability you need, so the dreadlord on dragon is kinda "wasted". Wouldn't it be better to directly field Malekith? he halves the wounds, and with his spell, he delivers mortal wound while healing himself: he's almost immortal! (now imagine Malekith'd dragon plus a War Hydra) Going for a different list, you can really optimize mortal wounds delivered by executioners... with the formation of the exiled blood cult, you can deliver mortal wounds also with to wound rolls, and a master with battle standard and Standard of Murder, can really help in that. Of course, you should use also witch elves, but the Cauldron is really made to work with them.