OoC: I'm going to roll this save for the sake of brevity.

Ilya Wisdom Save: 4

Ilya
As you push the first tool into the lock, you realize something. The door isn't even locked, and pushes open slightly at your touch. You feel a cool chill as abnormally cold air begins to rush out. You catch sight of something strange that confounds your mind. Past the at least dozen corpses that fill the room's floor, you see something hovering in the center of the room - like a tear in reality itself. A jagged rift in the middle of the air, its edges fraying into nothingness. Within the center of it you catch glimpses of an otherworldy landscape. Your head begins to hurt. A trickle of blood runs from your nose.

The door slams back shut as the pressure difference between the cold basement and warmer gradient on your side of the door forces it back closed.

You take 2 psychic damage.

"Whoa, are you okay?!" Glyp exclaims as Ilya is slammed back from the door "what'd you see in there??" Glyp focuses on the door, attempting to observe any magics that might lie within, but stops just short of opening the door again.

(Also of note, he would have handed an amulet out to everyone once we'd collected enough)

Ilya yelps and staggers, falling backwards onto the stairs behind her gripping her head. For a moment she just stays there, trying to quiet the roaring in her head. Finally she wipes the blood from her nose and pushes herself up. "I'm alright." She says to Glyptemis, though she takes a few cautious steps back away from the door.

"Something that shouldn't be there. A hole in the world, with something incomprehensible leaking out." 

She glances further up the stairs at the cautious ranger. "Door was unlocked already. I don't think there's anything living in there."

Lyra continues to lay the (horrifically) fallen to some semblance of rest, as futile as the gesture apparently is.

She relays to the others (pointing) where she sees the strange, complex symbol carved into the corpses (see spoiler in post 524).

Her harmonica remains silent, but even her whisper, though frightened, evokes a strange rhythm.  "Like flotsam betwixt ravening tides are we caught now, witness to the debris of a battle between powers and planes seemingly beyond mortal perception."

She pauses.  "Yes, LT, I too remember the stone rooms with horror.  What was done to us there... what we may have done there ourselves.  Some deep part of me screams to never to come near it again.  Or perhaps as you say, to revisit the site of that ritual last, only after clearing every other room..."

Yet as Ilya unlocks and opens the door, Lyra stands paralyzed, as if unable to speak or to take any action to stop her companion.  Deep down, she already knows something terrible awaits on the other side, a knowledge seemingly confirmed as the angel-touched woman recoils and the door slams.

Lyra summons her Mage Hand, ready to re-open the door, but does not yet.  "What did you see beyond, Ilya?"  The bard's query is a whisper.

Glyptemis
Beyond the door, you see a maelstrom of magic focused around the space Ilya described.

Kalamin reaches out with a healing hand to soothe the psychic pain Ilya was feeling before stepping past to the door. "Avert your eyes if you aren't ready." He says, reaching out to put a hand on the door. He gives everyone time to decide if they're ready to come face to face with this "hole in the world" Ilya saw before steeling himself and pushing the door all the way open. 

Wisdom Save: 22

Lay on Hands: 2 HP for Ilya

Quote from kohlmetz_d >>

That is until they determine where the storeroom is at. Focused on their resupply mission (ignoring the rotting fruit in the kitchen/food prep area) he looks around the area to determine what might be scavenged on behalf of the besieged Vinande. Anything useful he can find he gathers in the center of the room for movement later. 

The fruit and vegetables have spoiled in here, but you're able to find some grain and rice that have preserved well enough to take. You gather a sizeable pile to come back to - Vinande will be glad to have this later.

Kalamin
You step into the room, taking in the full terror of the tear in reality in stride. Beyond its horizon you see a shifting image: a yellow sky filled with black stars and buildings twisted into shapes that make no physical sense. It makes you feel uneasy, but you don't experience the psychic backlash that Ilya did.

There are four corpses dressed in ceremonial robes, the rest are dressed in regular garb and armor and seem to have been killed in the same twisted mean you've seen throughout the manor so far. Through the blood and gore you can see the remnants of a large sigil drawn on the floor underneath the rift.

Leftenant watches in horror as Ilya pushes open the door, seeing her injured brings the Ranger no joy though. 
As the door slams shut and Kalamin moves to open it once again, the veteran once again draws a hand ax from his side. He prepares himself to move in either direction, steeling his nerve. Forward to assist the old man…or rearward to beat the retreat, wordlessly he waits while monitoring the situation. 

"Thanks," Ilya mumbles to Kal, still rubbing her head even though the pain has faded. She follows him in afterwards, eyes on the floor at first until she gradually looks up at the cause of her shock again.

Quote from BlameItOnWinter >>

Glyptemis
Beyond the door, you see a maelstrom of magic focused around the space Ilya described.

 ( What school of magic would it look like? )

Glyptemis
Conjuration.

Ilya
This time you are able to look upon the tear in reality without ill effect. Your mind has adjusted somewhat to the strange impossibilities it offers, now that you're expecting it.

Wary of the rift in the center, Kalamin makes his way to each of the bodies, searching them for anything that might have related to the ritual that took place in this room. As he works, he glances back through the doorway to Lyra and Leftenant. "Does this room look familiar to either of you? You'd said earlier you remembered something of this sort I think."

Investigation: 15

Leftenant hears Kalamin call from inside the room. He had been apprehensive about this whole manor the entire time. Something in the back of his mind kept telling him to just leave, but honor demands service and he was an honorable retiree. 
Speaking with Lyra in whispered tones, “I’d have preferred more time and distance to determine what transpired a month ago. Perhaps some clarity would have provided insight to what we…how we contributed to this mess. I can’t help but remember Lucas’ words about what Lamb told him. If I may confide, I’m afraid.”

The old soldier looks to the steps and the chamber beyond. “But perhaps, since we are here, regardless of my feelings, that glimps of understanding will come if we return to the scene…of our crime.”

Raising his voice so Glyptemis can hear him as well, “Shall we join our comrade…together as one. And see if perhaps we had been here before?”

"Y.. yes, I think we should." Glyptemis walks with LT into the room with the rift, fixing his eyes on the tear in reality warily as he observes the flows of magic pulsing from it. "Everyone... be on your guard. It's possible that this tear is some sort of portal.. as in.. something could come out of it. Or maybe it already has.." 

Glyp strains his memory.. he knows from what they've learned that he was in this place, but how could he not remember this? Has he seen it before? Did they pass through this portal? He finds himself staring at the rift, almost hypnotized by the confusing and fascinating act of magic that's unlike any he can recall.

 Glyptemis
A wisdom save to attempt to recall your past here.

(Woof... natural 1 for a 0 on the wisdom save)

Kalamin
Among all of the attackers you find those amulets(9 total) - at this point you presume to be standard equipment for this group. As you look over the corpses of those in ceremonial garb, you don't find anything in the way of items, but there are some interesting things to note:

1. Among them is a man whose face matches the portrait you saw in the entrance to the manor. It would seem Lord Silvermane himself fell here.
2. They all bear a remarkable resemblance to one another, the other three were clearly also a part of the Silvermane family.
3. Parts of their bodies seem to have been morphed, transformed into weapons. A shard of sharpened bone extruding from an arm. The fingers on a hand reshaped into razor sharp claws. In Lord Silvermane's case, barbed tendrils that begin below his elbow and extend out to twice his own body length.

Glyptemis
The fog in your mind is too thick here. Maybe it's all the disturbing things you've seen today, you just can't seem to focus enough to push through.

"Lord Silvermane himself is here....And much of, it not all, of his line." He lifts up one of their transformed limbs for closer inspection, grimacing. "They have made weapons out of their very flesh. This isn't a form of magic I've ever seen before."

Kalamin takes a breath, looking around the room before closing his eyes and focusing. He tries to remember what happened here, what he saw.

Wisdom Save: 16

At first you only catch flashes as you look around the room. A dagger slicing across the skin of your underarm. Blood running down into a silver chalice. Chants. Screams.

Then the full memory comes back to you.

You see the other four: Juno, Lyra, Leftenant, and Glyptemis standing away from you at equidistant points in the ritual circle. You see five robed figures stand in a diamond formation around you, chanting in a language you can't understand. The pale woman: Maghda, goes to each of you with a ceremonial dagger, drawing your blood into a runed silver chalice.

She pours the collected blood into a black stone altar no longer present in the space, adding her own intonements to the chant.

You hear sounds of struggle from above.

Then the door to the basement blows open, and the assault team mentioned in Thalorin's journal moves in. Amidst the chaos Maghda clutches at a tuning fork around her neck, quickly speaking an invocation and grabbing one of the robed figures before vanishing. The rest of the Silvermane family's chant is interrupted, and their bodies begin to crack and change into the weaponized forms you see before you. The ritual was unfinished, but not entirely wasted.

The fabric of reality tears open above the black runed altar, slowly ripping wider and wider as the Silvermanes fight their attackers. One by one the Silvermane family falls. Lord Silvermane is the last, as a blade slashes across his throat. As one of the ambushers stands over him with sword held high, it arrives. A formless mass of flesh passes through the rift, shortly unleashing carnage on the assault team. Torsos snap, limbs explode, and bodies twist in ways that shouldn't be possible as the unknown monster seems to wield power of flesh itself.

All the while, you and your companions stand perfectly still, dazed or hypnotized.

The mass of flesh and fury moves upstairs as it finishes off the last of those that breached the basement. You hear the cries of its final victims before the manor falls silent. The flesh beast returns downstairs. And it waits.

Time passes. A day perhaps. Maghda returns at some point, regarding the undulating hunk of flesh with a raised brow. "Seidrach Karvas. It has been some time."

A ripple passes through the flesh, and a from somewhere beneath its mass a mouth forms. "My journey is interrupted. I cannot take a form of my choosing." It hisses. The pale woman regards it cooly for a moment, then nods. "These...Interlopers maintain a fortification to the west. See that they are no more, and take one of their forms as it pleases you. Then await the Promised Day. You will be called when it is time."

Maghda snaps her fingers, and a group of the pale elves come down the stairs. Some of them collect your companions, others the altar and chalices that were left behind, and finally one gently pushes on your back, guiding you back up the stairs as your vision darkens.

You snap back to the present.

(If Lyra is also aware of this memory, or if Kalamin shares it):

"So a singular extraplanar horror from beyond the rift effortlessly slew all of these attackers who bear the strange symbol on their flesh.  Maghda 'the Highblood,' the inhuman leader of the elves, addressed the deadly thing as 'Seidrach Karvas.'  But from what Ilya read earlier, they all worship another 'Seidrach':  this messianic 'High Seidrach Sotos.'  If the fleshy abomination was a 'Seidrach,' I have difficulty imagining what a 'High Seidrach' is."

Lyra pauses, looking pale.  "All they required of us was our unwitting compliance and our... blood?  For the ritual to summon it?  Are we... linked to it?"