How do you use hydras?

[Taqwus]

And different orders as well -- the hydras should be good to go immediately and attack rear or archers, while the non-chaff units are further back with hold/attack. Even then there will be friendly-fire casualties without a full poison-immune force.

I used perhaps an even dozen in my first game as Sauromatia. Kept them on a flank, relied heavily on archers (both national and banefire) and somewhat less on normal melee troops.

[Sheap]

Hydras will poison anything near them, so if you don't have a poison immune force, you have to use the hydras by themselves. Hydras regenerate, so you can use them alone vs. independents very easily, especially if you combine them with a priest that can cast fanaticism (so he can stand way back), or that has a poison resistance item. But, the indy hydras are small and weak compared to Sauromatia's, and don't hold up as well.

Hydras are frankly very awkward and difficult to use. I don't really recommend them, most of the time.

[curtadams]

After some efforts, I decided only to use them as part of a 100% poison-immune force. Normally I use them as part of an all-hydra strike force. They're unusual in being a fairly strong unit worthy of the late game (due to the regen) recruitable as an ordinary (if capital-only) unit.