[PvK]

It does take some doing to get Tartarians, but it's worth doing and there are death summons which can help many nations climb up to it. To get started you need a D2 mage, or a D1W2 or D1S3. Then you can summon something with D3, boost to D5, which lets you summon a D4, then you can probably find something to boost him to D7.

Then... you get to summon pretender-class guys for 10 death gems each turn. They're certainly worth GOR'ing and healing, but are very strong even without it, and give you more high-level random magic.