so, there's this level 45 evil mage...

[airwalkrr]

Gate can call in something with HD up to twice your caster level. Solars have 22 HD.

Dream Larva, perhaps?

Meh, pick your own HD x 2 abomination as long as the DM allows it. It was just the first thing that popped into my head. And besides, solars might be happy to assist in a more long-term agreement without additional payment given we are talking about a really f-ing evil mage here.

 

[Jacob]

Gate can call in something with HD up to twice your caster level. Solars have 22 HD.

Dream Larva, perhaps?

So not only should the party of 25th Lvl PCs have gotten blown to smitherens, but just one of his spells could have killed them with living nightmares? That's something to ponder alright.