
Ynaeve Amryln |

I never actually died, so correcting for the first hit missing, I was at -27, healed for 27, puts me at zero. Another CSW puts me at 31.
Ynaeve finds herself prone, badly injured, and her staff and wand are laying on the ground. She'll scramble for those if the Merilith is out of range, then stand up.
That should be her actions for the round.

MiniGM |

8d20 ⇒ (2, 17, 10, 18, 5, 7, 2, 5) = 66 The Marilith lays into Belsiard but only manages to hit him 3 times
2d6 + 19 ⇒ (6, 3) + 19 = 28
2d6 + 19 ⇒ (4, 2) + 19 = 25
2d6 + 19 ⇒ (2, 1) + 19 = 22
The Glabrezu that had been fighting Bariel has a choice of 1=Bariel or 2=Ynaeve 1d2 ⇒ 2
The Glab unleashes it's full fury on Tarwas 6d20 ⇒ (1, 1, 6, 7, 7, 14) = 36 all the attacks miss
the Vrocks dance for the 2nd round in a row
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Belsiard attempts to cast a spell defensively 2d20 ⇒ (14, 10) = 24 and he penetrates the SR of the Marilith with a hold monster spell 1d20 ⇒ 4
The Marilith plummets to the ground held.
2d20 ⇒ (3, 13) = 16 Silk flings his two daggers at the Glab attacking Ynaeve hitting once popping an image
Go Heroes
considering the Marilith is held,this fight might be over, especially if it fails a second round
De Witt channels 3d6 ⇒ (5, 3, 1) = 9

Bariel |

Seeing the mightiest of the evils present in the room fallen to the ground but not yet dead, Bariel springs into action. mythic spring attack, get two attacks on it and no MP cost. trying to do so when he can get a flank on, but her being held probably gets him his sneak attack anyway. as a bonus if he gets the flank with someone else they get +4 instead of +2 for flanking
Fighting defensively plus combat expertise = AC 40
acrobatics to avoid AoOs: 1d20 + 35 ⇒ (9) + 35 = 44 (AC 44 vs AoOs)
atk: 1d20 + 24 ⇒ (18) + 24 = 42
dmg: 3d6 + 6 ⇒ (2, 4, 4) + 6 = 16
snk atk dmg: 8d6 ⇒ (1, 3, 2, 6, 6, 5, 6, 2) = 31
atk: 1d20 + 24 ⇒ (16) + 24 = 40
dmg: 3d6 + 6 ⇒ (1, 6, 1) + 6 = 14
snk atk dmg: 8d6 ⇒ (2, 6, 5, 2, 6, 2, 2, 4) = 29
confirming 18 crit threat: 1d20 + 24 ⇒ (2) + 24 = 26
bonus dmg if confirmed: 3d6 + 6 ⇒ (1, 3, 3) + 6 = 13
moving back to starting space due to spring attack
TL;DR:
Damage if 26 hits a held Marilith: 43
Damage if 26 misses but 40 hits: 30
BONUS: if sneak attack is in effect: +60 damage to applicable above total.

Tarwas, E’Sum Tel Myth Drannor |

Why does she fall to the ground? Paralyzed creatures only fall if they are winged, not if they fly by magic. She might even still be able to fly around (purely mental, though rather clumsy. Flight skill with (effectively) dex 0 might be hard to do...).
You also forgot the unholy aura(str damage, Bariel might be encumbered and severely limited in his dex after one hit).
Also, what happened to the mirror images on her?
Tarwas keeps attacking the smaller demon.
normal attack routine
sr: 1d20 + 18 ⇒ (16) + 18 = 34
sc vt sac bos: 1d20 + 27 ⇒ (2) + 27 = 29
1d8 + 17 + 2d6 + 2d6 + 9 + 3 + 42 ⇒ (1) + 17 + (2, 6) + (3, 5) + 9 + 3 + 42 = 88
1: 1d20 + 27 ⇒ (1) + 27 = 28miss
h: 1d20 + 27 ⇒ (5) + 27 = 32
1d8 + 17 + 2d6 + 2d6 + 9 + 3 ⇒ (7) + 17 + (3, 6) + (3, 1) + 9 + 3 = 49
2: 1d20 + 27 ⇒ (13) + 27 = 40
1d8 + 17 + 2d6 + 2d6 + 9 + 3 ⇒ (4) + 17 + (3, 6) + (2, 2) + 9 + 3 = 46
3: 1d20 + 22 ⇒ (7) + 22 = 29
1d8 + 17 + 2d6 + 2d6 + 9 + 3 ⇒ (7) + 17 + (1, 2) + (1, 5) + 9 + 3 = 45

MiniGM |

Tarwas attacks vs images his first attack misses but hits an image
1 1d4 ⇒ 1 pops image
2 1d3 ⇒ 3 hits
3 1d3 ⇒ 1 pops image
Tarwas I am starting to see what haste does not stack with spell combat and starting to agree with it. it will stay the same for this fight, but next fight haste will not stack. Sorry.

MiniGM |

if you would like to rebuild talk to Ynaeve about doing once we level up. I do not mean to sound like a jerk here tarwas but I feel like you are constantly questioning me. I volunteered to keep this game running when nightskies had to leave, making all of my preparation worthless and I would appreciate a little bit of help here. If I am making a mistake that is going to cause a huge problem for you, like death. Then fine, but other things benefit you as well because I play them the same for bad guys and pcs.