Which combined artifact is the best?

I really messed up when I said that the Titan's Roar is great. Because it's almost useless for a mage hero (600 damage in the later stages of the game is not even comparable to a lightning bolt). In general, I've been playing Necromancers a lot lately, so I try to collect powerful neutral creatures (and considering that there are cartographers on random maps, finding something doesn't cost anything).