She IS currently helpless but uses nature against people. Also, if she gets mad or sad nature starts to die. Which means the fruit and plants stop growing.
And If Sooth can convice Lacie then *Shrugs* She might.
All you need is faith, trust, and a little bit of pixie-dust!
... seriously, what could Sooth use as leverage? if both she and Ingrid work for him... Sooth will be nigh unstoppable. I hate it how his minions seem so sucky (when they're not), so I need to up the ante.
Hm. If he tells her she could have all the nature she wants or that no one will hurt nature then she might. Or he could say that she'll be better protected or something. Lol. She'll do anything for Earth.
All you need is faith, trust, and a little bit of pixie-dust!
I tell the neophyte: Write a million words–the absolute best you can write, then throw it all away and bravely turn your back on what you have written. At that point, you’re ready to begin. — David Eddings