Chonk, finally free from the paralyzing fear, moves into a position flanking the beast. He proceeds to attack it with a flurry of blows, trying to find the squishiest parts. 

Attack: 22 Damage: 7 

Bonus Action: Flurry of Blows 

Attack: 23 Damage: 4 

Attack: 18 Damage: 5 

Sindri your mage hand floats across the room and closes the book without a problem. The glow of magic begins to fade from the room, leaving only the mundane torchlight in its place. The creature howls as if in sudden pain.

Chonk you charge in with unbridled fury and land hit after hit on the raging beast. It is looking really hurt. 

(With the book closed the lair actions are over, Sindri take inspiration for that one!)

Lefaris and Guroz you are up!

The abomination surprised Lefaris as it leaves the small room and comes out of it to attack her. The first strike skims off her leather armor, but the second slashes deep, leaving bloody riverlets running down her side. She sees the thing react though as the book is closed. "Is it all the book, or what?" She calls out, taking a defensive stance, looking to the creature. "If the farmer is in there somewhere, please come out before we have to hurt you further..."

Lefaris takes the dodge action...

Guroz is silently impressed by the motion of the dwarf, and attempts to imitate in his own way...

Attack: 10 Damage: 8 (slashing) 

Action Surge - Attack: 9 Damage: 6 (slashing) 

Lefaris roll persuasion as you try to get through to the beast.

Lefaris persuasion: 9

Chonk hopes that the creature’s will to survive and the possible discontinued corrupting effect from the tome will tilt the balance in the Wendigoat’s mind to accept defeat and surrender.

Sindri breathes a sigh of relief after seeing the effects of closing the book (thanks for the inspiration!) and starts calculating her next move.  She sees Lefaris is in bad shape and is going to see how she can help her...  

Lefaris, the creature is too enraged to heed your words and continues its onslaught. 

Guroz your attacks while ferocious do not hit their mark as the beast writhes in pain and anger, avoiding your blows. You get its attention however as it turns back to you with two vicious attacks. Attack: 14 Damage: 5 and 10 Damage: 6

"Where's Papa?"

You all hear a loud PWOK! and see the child entering the room  behind you all, holding the chicken to their chest. Their tear stained eyes fixed on the creature. The beast gives a terrible howl and begins to move.

You are all up!

Chonk, fearing for the safety of Child doesn’t hesitate to strike the beast with his opportunity attack (assuming the movement above was to approach Child and that the Wendigoat is no longer flanked for advantage purposes). He will, however, be striking non-lethally to knock the creature out, aiming for what he would imagine are nerve centers in the neck and spine. 

Opportunity Attack: 19 Damage: 7 

His action in initiative follows, should the opportunity attack not stop the beast.

(I figured from what was written that Lefaris was shooting from the doorway, Sindri you have not moved since entering. Chonk moved to flank and Guroz followed the beast up from the back of the room. I will wait for the rest of you to post the round up before posting a response).

"This is your father." Lefaris tells the child as she continues to block the doorway, making the thing go through her if it wishes to get to the child. "If we can get him to calm down a bit, we might be able to resolve this without anyone needing to get hurt. Can you help us?"

Turning back to the creature, Lefaris was not quite sure if she was right or not. For the child's sake she hoped so, but the glimmer of something else inside the beast was just so small. Maybe one more try to get through to it... "Farmer, if you are in there, please don't make us hurt you any further..."

Persuasion: 19 / 21 (rolling twice in case the child gives advantage on the check...)

Sindri now seeing the Guroz is now in worse condition than Lefaris after the beasts last attack, uses her healing light to help.  A glow appears above Guroz and 5 of healing seep into his bones.

Watching as Guroz uses nonlethal force against the creature, Sindri worries that the only attacks she has cannot be used in this form.  She instead yells to the child, "Stay there, we are taking care of the beast that has captured your papa!" and casts minor illusion in the space between the two rooms creating a door between them and if allowed, a sound that "locks" the door.

She then tries what Lefaris did, "Please, see your child?  Come out and beat this thing that has taken over you!"  Persuasion 17

(If that last was too much, just forget it then)

Giving Sindri a slow nod of appreciation at the healing, Guroz agrees with the groups change in tactic.

Guroz holds his action, if the creature attacks anyone else, he will swing with the flat of the great axe (non-lethal damage).

Lefaris the child looks horrified by your announcement that this beast is her father and she backs away a little. Your words to the monster are met with a vicious snarl. 

Sindri your spell saves Guroz from going down and following on from the words of Lefaris you seem to be finally getting through. It falters and grows quiet, but is still in a state of pain and confusion and tries to move forward toward the illusory door.

Chonk you release your non-lethal blows supported by Guroz and the the beast crashes to the ground unconscious. 

As you all stand over the still form of the beast you watch as its form begins to shift and shrink. Its wholly exterior fades away to reveal humanoid limbs and the familiar bulbous nose an bald head of a villager.

"What is happening?" you hear the child cry from beyond the magical door.

Sindri steps forward and tries to help heal the man now that the beast form has left him.

Healing Light 3

She hopes this makes a difference, and if it appears to, she'll head to the "door" and remove it so the child can come in.

Sindri, you see the various wounds close up on the farmers body and they groan softly. 

Releasing the spell the child runs in and falls to their knees next to the farmer. "Papa! Papa are you ok?"

Is there anything you would like to do while the farmer is coming to his senses?

Chonk will approach the acursed tome and remove his backpack. He will open the main pouch and prepare his walking stick to scrape the book into the open pouch without having to touch it with his hands. Before he makes contact with the book, he looks back to the spell casters,

”Do you think putting this book into this special space inside the pack is safe? Could it help break whatever other influence it might have here?”

Guroz would swoop up the child, trying to calm them down but without denying them the truth, "hey kid, your papa's real hurt. But we going to see if he's okay. We'll just wait by the stairs and they'll come and get us, alright?"

The half-orc takes the child, trying to keep him talking and distracted from the state of his Papa. 

Lefaris moves around the chamber, looking for anything else that might be best not around when the farmer wakes up fully...

Perception: 5