[Saber Cherry]

Then there's the obvious answers. Ryleh has expensive leaders and large, expensive units, and cannot use indy leaders. The large, expensive units are ranged.

Ctis uses nature, astral, death, has one of the best assassins in the game, and has poison-resistant units. So...

1) Give assassins antimagic items, and assassinate Ryleh's leaders with skeletal swarms.

2) Use poison-cloud-ish spells, or foul vapors.

3) Cast swarm, and interrupt the mindbLasters with dragonflies, forcing them into melee. You can even curse them first, so even dragonfly bites will cause problems...

4) Cast antimagic. 1 gem (probably 2 for you), largely negates Ryleh. Or did you play an astral nation without plannning for the ability to reach Astral 2?

These are some pretty simple solutions. The best is probably crossbows, but you seem to have discounted that already.