The work you’re doing is much appreciated! Love having this available 
Thanks! If and when the new challenge dungeon is out, I’ll be back with more updates.
I also plan to add abilities/stats for monsters, as soon as I find an easier way to look those up than having to muddle in asset manager.
I have been loooong overdue with posting the Ancient Grove monsters, but for some reason, I always kept delaying it. So best post it now before Forgotten Realms is out, 'cause I am gonna cover the next expansion’s bestiary too.
This time I rather used the editor to take close-up screencaps of the creatures.
Let’s start with Basilisks!
Aethertongue Basilisk (Aether Corruption - Common)
These are the most common basilisks, melee only. They do Aether and Physical damage, and have a charge attack.
Aethergaze Basilisk (Aether Corruption - Champion)
These are ranged attackers like the poison-spitting variants, but they spit Aether projectiles that also reduce your damage for a time. They can also fire an Aether/Poison wave.
Aetherblood Basilisk (Aether Corruption - Champion)
The largest versions, they have a short range Aether breath that can stun you and cause fumble. They also have the longer range gaze attack that Stonegazes have, which petrifies, slows and reduces % health.
Slathsarr Aethergaze (Aether Corruption - Unique)
You can find Slathsarr in a small death room arena locked by vine doors in the middle of the Feral Thicket. It is a mostly ranged attacker monster that fires Aether/Acid/Physical bolts like a machine gun. Also spawns acid-dealing gas clouds, fires an Aether/Burn wave, an Aether/Fire nova, and even has a damaging Aether aura. Worse yet, ranged attacks hitting it have a change to trigger more Aether projectiles…
Can drop Slaathsarr’s Crest, a nice medal for Arcanists that converts all elemental damage of Panetti’s Replicating Missile to Aether, and also adds weapon damage to the spell.
Nice guide and kudos for all the effort but I’ve read the first page and there’s nothing on Cannibal Bloodsinger about his full heal or on Ghost Crabs about their disrupt - and those are their signature moves. And Javos Bonesplitter - he has phys/vit 3proj shotgun autoattack, a petrify with a debuff and a stun with phys dmg. You can consult gt if you don’t know.
If you check back, when I started the guide and posted these, I don’t think they had the monster database up yet - there was only the wiki. I tried checking the editor but skills in there are displayed in really confusing ways, so I mostly just guessed what monsters do based on what I encountered/noticed with my characters. I was planning to go back and add detailed skill descriptions but again, lack of time. But now I can have the GrimTools database so I can list the skills - it is often confusing still because they add all the passives and a lot of proc skills there, and you cannot really know what these do unless you experiment and let the monster attack you.
Btw, I only noticed that the Bloodsingers do some weird exploding aura thing when they die, which does not seem to damage my character, I never guessed they would heal others with that.
My bad, I didn’t do that. It just popped up and I assumed it was new. Sorry for that.
Let’s continue with the Basilisks tained by Chthonic corruption!
Voidtongue Basilisk - Common, Chthonic/Beast
These are melee attackers, they have a charge attack and do physical+chaos damage. They are resistant to chaos attacks of course.
Voidgaze Basilisk - Champion, Chthonic/Beast
These attack at range, firing physical/chaos damage projectiles that also debuff you and decrease your damage. They can also fire a short range wave similar to what Ryloks use, which does chaos/poison damage and slows you.
Voidblood Basilisk - Champion, Chthonic/Beast
These are the toughest Chthonic Basilisks, they attack at range causing physical/chaos/internal trauma damage in an area, plus can stun you with their base attack. This attack also debuffs you to cause fumble and impaired aim.
Their more dangerous but longer recharge attack is similar to Stonegaze Basilisks, causing % HP reduction and a chance to be petrified.
Lastly, they can buff themselves and nearby allies to heal % damage and increase speed.
Let’s continue with the kitties! Now, we have already seen Fleshwarped Manticores outside the Ancient Grove, but their Void-tainted cousins can only be met here. Like all manticores, they too are immune to Fear effects.
Void-Tainted Manticore -Common - Chthonic/Beast
They are your classic kitties, just more chaotic. Their attacks do physical, chaos and bleeding damage and they are pretty fast.
Void-Tainted Wastestalker -Champion - Chthonic/Beast
Similar to untainted Wastestalkers, they have a Shadow Strike-like ability where they disappear and rush to you for a powerful attack. This does Acid, Posion and Chaos damage. Their regular tail strikes do such damage too (plus physical) and also can slow you.
Void-Tainted Alpha -Champion - Chthonic/Beast
They cannot rush-attack like Wastestalkers, but instead shoot a wave of Chaos at you that does Chaos and Vitality Decay damage. Their basic tail attack does Chaos, Physical, Acid, Poison and Bleed damage.
And also like regular Alphas, they can boost themselves and allies with a buff that gives them Damage absorption, speed, defense and extra Chaos damage.
Ragarroth the Tormented -Unique - Chthonic/Beast
This unique Manticore boss always spawns in the same spot, the circular arena in front of the Challenge Dungeon door in the Ancient Grove. So you will be fighting him a lot! Also the Coven gives out a bounty for his destruction to free him from the Chthonic possession.
Ragarroth attacks with his own Chaos version of Savagery that increases in damage the more he hits you, and does Piercing, Physical, Chaos and Bleed damage (plus reduces a % of your health). This and all of his attacks can create a churning pool of entropic void under your feet that does Chaos and life reduction damage plus causes Impaired Aim.
His claws/tail strike (when he rears up and charges) does Pierce, Chaos and Bleed damage, and also slows movement speed and reduces defense. He can also do a Shadow Strike rush which does Pierce, Chaos and Bleed damage.
And when push comes to show, he can also summon 4 Voidlurker Pestilences.
Oh and let’s not forget the arena you fight him in is littered with exploding puffballs that leave a poison cloud behind!