Ok, guys, I f***ed up.
After some magic research I find out I embarked on a biome with the "life" sphere of influence. So I start the usual channeling stuff to harvest the various effects (plants grow quickly, injuries heal faster and easier, the usual good stuff).
Of course, I leave the channelers working for a while and I forget to check. It turns out my embark is not only in the "life" sphere... About a third of it (of course the part where my channelers are) is in the FIRE sphere.
So now I have flaming trees everywhere on the surface, the biome went from temperate to hot (yes, I'm dumb, it took me THAT long to notice) and the special children who are born here don't heal those next to them, and they don't calm ghosts either; no, they set fire to something next to them every time they get a bad thought.
On the bright side, though, they have fireball attacks, and it looks like they are immune to lava (I still have to test with dragonfire), so in some years I'll have my army of pyromancer warriors ready to kill any human approaching (let's see if your gunpowder is still a "technological advantage" when it blows up in your face every time you bring it here. This may give me the edge I needed to have a chance in the war)