Ctis has one amazing advantage:
Most of their troops require almost zero resources.
So you can use Sloth 3 and get additional points from the heat scale.
Furthermore your mages are quite formidable too and you don't really need other magic since you already have death + nature, atm in my ever changing opinion imho the 2 most useful magic paths
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With CB 5 i think one lvl 9 bless is most useful. Either F9 or W9.
Especially F9 is cheap and useful:
Moloch, F9, Watchtower, Dom 6, Order 3, Sloth 1, Growth 3, Heat 1, Misfortune 2, Magic 3.
That are economically quite good scales. Very useful for Ctis. The offensive power of both your serpents and your serpent dancers is considerably strengthened.
The snakes will still quickly die but you can replace losses fast.
The Snakes are quite dangerous vs. many Thugs/tough troops also.
With their 18 attack they hit rather often. With their flaming weapons attack they also hit etheral beings.
And then their is their poison.
So a Thug has to be poison resistent and has to have either high protection or fire resistence to easily slaughter the snakes.
The main Question is though if they are really useful for faster initial expansion. I think ctis with really good economic scales is even better. 1-2 Armies expand with Slave warriors or falchioneers and then you get your skeletonspamming sauromancers.
My estimation would be that ctis without a bless strat works even better then normal ctis.