Once we have some basic footholds, we can put up a forest full of friendly critters to act as the greeting crew for fey saboteurs.
Classics like
Tintargurills, with their specialty fey hunting tools.
Nachzehrer if we can swing them, because fey vampires that can summon zombies from areas where fey and humanoids have died are fun. Plus they have some stuff for blending in with regular fey at need.
Lots of regular oak trees to support a
Quick wood population. These guys have the ability to see through any oak tree within 360 feet and can absorb magic cast on them, so they make for great greeters.
Sprinkle in some
Gallows Trees to entertain any surprise guests sneaking around and we'll have a decent welcome mat waiting for them.
Optionally, we could also include a few
The fact that it's covered in torture webs, and inhabited by a mix of vampires, all seeing trees, and the reanimated corpses of previous trespassers will just add to it's charm.
Edit: removed extra word