Minotaurs are strong warriors, but their strength - wild nature and desire to better one another was always their weakness as well, strategy of any kind is not their thing, they tend to concentrate on one opponent. Organized defence was not something those three were ready too and M3 was the first one to learn it the hard way. Three (grunted - enhanced) strikes from Fran, and already wounded by all sort of magic Minotaur dropped down splashing water and blood all over the room.

(Redirecting Polly's spell to M2, as M3 was down. M3 Save: 9, vs prone M1: 6 M2: 12)

Adray, to much surprise of M1, did not even flinched under the heavy blow - an invisible force made the axe slip. Instead, with a few precise moves he dropped both bulls in the water, where combined attack decimated the enemy.

The battle was over in just a few seconds. In a sudden silence all you could hear is incoherent mumbling of the man in the shining helmet.

Choir dusts off her feathery hands, puts away her mace, and attempts to pull the helmet off the mumbling man.

It does not work - the helmet does not move an inch, and the man seems lost in his inner conversation (or whatever he is doing).

As the last of them went down, Adray takes a deeo breath, his eyes in the creatures.  He looks up at the portal.  "Nice work everyone, another skirmish one.  Nibs, lets move the corpses infront of the portal.  Maybe it will trip up the next group to run this way or buy some time if its smaller creatures"

He turns to the others, "I dont know what he's saying but translate what ya can, reason with him if you can and if nothing else we'll restrain him.  Polly?  Can you tell anything about the portal?"

Ordrag starts dragging the corpses of the soldiers to the portal, piling them on top of the minotaur bodies, but checking for anything worth salvaging at the same time. He again suggests: Maybe him too close to portal, speaking all that demon-talk. Maybe drag him out of here first. 

Polly will move over to the portal and inspect it. 
arcana: 23 

“hmm maybe, do you want me to try and close it?”

would Polly know if a dispell magic would work on this portal? 

No mage had opened that portal - it is work of faith. There is no chance to close it with anything party has (or ever?). It is clear, though, that the power of the portal is now tied into the helm, and to the man wearing it (no one of you have seen Duke Ravengard before, but the fine clothes and armour the man wears make him a good candidate for the name).

The words that man mumbles, the voices he makes, the struggle he is going through - all reveals that the psychic struggle taking place within man's mind is between some divine higher power and a terrible, demonic entity. So powerful, in fact, you are sure that no simple spell can break this hold — but that a more involved ritual might free him and probably even shut down the portal by allowing the power of Torm to sanctify this area once more.

Lulu, hovering above the man with her (sadly useless) aura observed him for a while and finally admitted: "I can not help him."

”neither can I. I’m afraid this is a matter of faith.. can you do something choir?” 

Fran would hover around the others, listening and inspecting to ensure she was following along. Though, it was clear there was nothing within her wheelhouse on this one. If it were a matter of faith, she’d look to Choir and Ordrag now. Should there be any support she could provide, she would. Otherwise her and Brutus would work together as lookout. 

Choir scratches her head. Remove Curse did not work.  Trying to remove the helm didn't work. 

She does the dice rolling ritual dance, casting the sparkly red dice to determine if it would do any good to push the Duke through the portal. ( Augury )

If the dice don't offer any hope, she will try another prayer to Torm. Lannis Fogel's helmet is connected to him.

Ordrag suggests they get the duke out of here before more demons show up. He tries to pick up (Or Drag) the armored human.

Athletics: 10

Wow, him is heavy!

The man is heavy - clearly a warrior, and well armoured too, but he does not resist dragging, can eve move his legs somewhat, though does not seem to see where he is moving and if left alone drops down again. 

Fran would see Ordrag try to drag the man and the man possibly even move his legs to help. She’d approach to lend a hand to help carry the man out of the water. 

Adray would lend an arm to help pull the Duke along as well.  Suggesting that Nibs take one arm and he take the other that way should he turn violent they will have a good grasp on him.

Athletics 22

With advantage from that help 25

Choir's dice firmly set on the most negative outcome to her question, but prayer to Torm cleared her mind enough to remember about rituals of exorcism, that any church on any benevolent god on the face of Faerun usually offered. Herself Choir never participated in one, but those acolytes the party saved before? Who knows, after all, they were clergy of the High Halls.

(Meanwhile, the man in the helmet did not demonstrate any sign of aggression and Ordrag, Adray and still enlarged Fran pulled him out of the pool quite easily. He did not seem to notice, though) 

Polly stand by Choir, curiously watching her cast her die.

Choir shrugs. She had not really thought pushing him through the portal would be a likely cure, but she was glad she had checked. Rattling her sparkly red dice, she follows Ordrag, Adray and Fran as they drag the duke away, hoping that his followers will have better resources to help him. The possessed helmet somehow reminds her of the Huddle Lord in his shield, and she sighs slightly, hoping that whoever had the wonderful item now appreciated its flawless, shiny surface and clever inhabitant, and was doing good things with it.

Assuming "out of here" meant "out of crypt". The Duke (he still could not say anything, but the probability of this man to be the Duke was quite high) obediently or more like absentmindedly (literally) was hanging on Ordrag and Adray all the way to the stairs and up. At the top of the stairs you found Gedeon and his little army - patient as a grave. His face expression did not soften when he saw the helmet and recognised one of the man that went down earlier.

"I see the fool that disturbed the portal. Why did you drag him here instead of killing?"

“Why would we kill him? He has people relying on him and he is one of us..” 

Polly has a bad feeling about this Gedeon, she does not trust him and is ready to take action if necessary. 

Cold deal unblinking eyes stared at Polly from almost 2m height: "He did not came here with you, he came with others - those who disturbed the portal. Now where are they? Dead, aren't they? Yet he lives - and he speaks demonic words. Even if you do not recognize them in your ignorance - they do come from demons. Did you close the portal?"