Thea 2: The Shattering Easy Kindergarten Achievement

Thea 2: The Shattering the easiest way to achieve the Kindergarten Achievement on any difficulty. It's probably not how "it's meant to be done", but ah well.

Steps

Start your game as Nyia and the two kids. I also had "Mithril goat", which gave me a good axe later on, but that's optional. 

Once in-game, proceed to kill off both your children asap. You'll now be left with one undead dude (the chosen child), instead of two children - more or less equivalent of a warrior. What happened to me when I did this was that my undead guy (+girl?) had sex with himself, so I quickly had two undead instead of two children. This made surviving 100 turns quite easy.

You might get away with letting one child live too I suppose, I just haven't tried it.

Guide by Avien