Im guessing vermin is like rarabs. I havent seen any rats or anything of the like yet... ive only been to about half the areas in the game so far though. test it out, see if you do more dmg to them now that you got it.
them being intimidated means that they are in fear and won't attack u in that turn... so u get a free hit at them... the more intemidated they are the better it is for u... and now to my quetion... what are the Amorph ? Smiles ?
being lvl 10 BST really helps helps in Farmming espacilly when hunting Crawlers :D
the vermins are insects like bees for example. theres is a diagram in windurst woods all the way North around that thief girl nana minho whatever her name is. Its where there are three mithras surounding a table. it shows you what type of monster is superior to another type. i went and copy the diagram on a piece of paper for quick reference. if you do it right; your pet will intimidate the monster you told it to attack.