[AreaOfEffect]

Renojustin has the right idea. The largest advantage of MA Caelum is their mobility. The best way to utilize that mobility, in my opinion, is with intel. By using an abundance of scouts you can often avoid risky confrontations and lead armies away from your goals.

One of my favorite tactics is to use my ability to leap over armies as a means of surrounding them. Then by employing several fear effects, make them all retreat. This often involves the use of death mages. You can create revenants to cast Frighten or enhance a High Saraph to Death 3 with forged items, equip them with 2 death gems, and have them cast Wailing Winds while your army pelts the enemy with arrow fire.

My favorite of all fear effects however is Dark Skies. It has the major drawback of being a world enchantment, but if strategically cast before a big battle in your own dominion, it can sometimes win you a war. (Not on it's own of course.) The Virtue is the best pretender for a Dark Skies caster and luckily this god is available for MA Caelum. Still, as much as it is a whole lot of fun, I can think of better pretender designs.

Honestly, your evocation spells combined with your shock resistant troops and a lightning storm is probably your biggest national gun. It will be rare to find shock resistance amongst your enemies. Cold and heat resistance is much more common and much easier to achieve. Even most shock resistant troops aren't really immune.