So, in both the lists of prismatic walls in Arduin I and Arduin V there's the Green and Yellow (or Greenish Yellow) wall which works against everything related to dragons. Dragons can't physically pass it, their breath weapons are blocked and even their magic cannot pass the wall. The only way that a dragon can destroy this wall is to cast a "Trigger" spell at it, and that's the rub. Both the entries for this wall in Arduin I and Arduin V reference the Trigger spell, but don't explain it. Arduin I references it in a footnote as "the aforementioned trigger spell," but I can't find where it's previously mentioned; considering that this is the Arduin Grimoire, it's conceivable that this is just talking about the entry of "Trigger spells" (is the plural a typo? it's the only time I think I've seen it plural) in the chart that it references, or that Hargrave forgot to flesh this out, but I'm hoping not, and it's also Hargrave's style to totally explain himself, just in a place you wouldn't expect, like he does with "competence." I've tried looking around and reading anything that seems like it might be relevant, but I haven't seen anything about trigger spells. I realize this is an obscure question but does anyone know anything about this?