sauromantia

[Belac]

I am fighting a war against Sauro in one game (Mooseknight), and nothing made me happier than when my opponent ran out of money for more hydras. A couple hydras plus high PD plus a few skelspammers was enough to require me to commit whole armies of mine (admittedly, I am agartha and using national units), and combined with any other Sauro force was enough to defeat me as the hydras+skelspam held my forces up while the PD archers slaughtered me.

It stopped working once I was able to get enough elementals+umbrals, but for early research and secondary fronts (send a few hydras on a raid, drop some PD in their province and attack the next--it takes disproportionate force to defeat them, and either you face them+PD or just the PD, which weakens your force for when you do catch up. That's not terribly gold-cheap, but it's cheap on everything else and seriously draws enemy resources away from the battlefront) it was awful.

[BigDaddy]

Some people get really upset when certain type of units, especially expensive ones, die. But, if you get 10knights to die from running through the poison of 2-3 little hydras, you probably did just fine.

[Squirrelloid]

Hydrae, like elephants, are actually pretty easy to counter, assuming you're playing a nation that isn't totally crippled. (So Belac's EA Agartha has plenty of excuse to hate the hydrae).

Agree with Trumanator - you build them to counter specific units (and then preferably get them killed as soon as they're no longer useful).