Ismark is going to use his full action to fight through the winds and move up to Strahd. Strahd ignores him and uses his first legendary action to move 30 feet up the stairs.

Gertrude is up.

Gertrude flies so that she's 45 ft away from Strahd, staying where she is if she's farther.

Gertrude adds some distance between herself and Strahd. (Also assuming that Gertrude flew above Strahd in order to not provoke while she moves.)

Strahd will use his second legendary action to attack Fae.

Attack: 19 Damage: 18 This damage is necrotic and if Strahd hits, Fae is Grappled. DC18 Athletics or Acrobatics to escape.

Emil cries out as Strahd approaches. "Master! Forgive my failures as I fight aside you!" And he shifts into the form of a horrible creature that's a cross between a man and a wolf.

Strahd will use his third legendary action to try and attack Samael.

Attack: 17 Damage: 23 

Samael is up.

(Hit)

Samael grimaces as he takes the vampire's blow, but channels unto himself everything he has. In a moment, he sprouts a pair of radiant angelic wings, the lines on his body also becoming a radiant gold color. (Radiant Soul)

Hadrian is up! Strahd is currently in melee with Fae and Samael.

Hadrian runs up to Strahd and lays down the magic circle, which is set to keep undead from leaving. Glyphs appear on the floor in a circle, with Strahd in the center of it. Hadrian is about 10 feet away from the edge of the circle. 

The scroll dissolves in Hadrian’s hands.

Strahd is trapped in the circle with Fae and Samael. "Foolish mortal, this circle cannot hold me!"  Doremor is up!

Doremor nods thoughtfully as Strahd speaks, "I'm sure, that's why I'll just be waiting out here. Samael! If you would turn the light onto our fine host, that would be wonderful."

He casts Hunter's Mark on Strahd before shooting him with his shortbow.

Attack: 18 Damage: 30 (Mundane piercing)

Doremor's bolt impacts Strahd, but he doesn't seem to bothered by the bolt and tears it right out of his body. Strahd is going to use his lair action to pass through the floor and escape the magic circle.

Charisma Save: 24

Strahd is easily able to overpower Hadrian's spell with his dominating force of personality.

Fae is up, Strahd has currently phased into the ground.

 Fae scowls and stomps towards Emil. "You're annoying." She whacks him with the thigbone and a kick.

Attack: 27 Damage: 9, 6 extra radiant damage if he's a fiend.

Attack: 11 Damage: 9, 5 extra radiant damage if he's a fiend.

Attack: 14 Damage: 7

Samael22,Hadrian22,Doremor21,Lair20, Hound of Ill Omen18, Fae16,Strahd13,Belzo10,Ismark9,Gertrude8,Emil5

Baleful red eyes watched its prey disappear appear from sight. And yet, no matter where the vampire went, Bosco the Hound attention jerks towards the direciton Strahd is, and would make for the position; phasing through solid ground if need be to get within biting range of of the vampire.

Movement: (40ft, for whatever it matters. Can move through solid objects as if difficult terrain, but takes force damage(5) if end turn there)

(If able to move within range)
Action: Bite Attack: 20 Damage: 10 non-magical damage.
(Flat roll, since neither can properly "see" the other in solid stone)

Fae's first and third attacks hit! It's not a fiend, so no extra damage.

Belzo's hound misses, because it's hard to fight when both of you are in the floor.

Strahd will spend his round passing through the floor and arriving in front of Doremor.

Belzo is up.

Belzo grimaces and holds a hand up to the light. "Get close and get burned, or stay away and be isolated...Bloody Hell." He mutters, then takes a deep, deep breathe. Shadows throughout the room peel off the walls, drawn to breathe like a moths to the flame. Though when he stops, what hasn't already entered his being, snaps back into place as if nothing happened. With eyes of pitch black darkness, he regards his surroundings, and casually digs around in his pocket with a free hand.

"I do not suppose anyones got any smokes?" He asks. Yet as he does, Samael's form gains a blurred edge that only becomes more pronounced whenever he moves about. "... Oh great. Either that candle light just got brighter, or I'm seeing things." He adds, frowning, and after a moment, reluctantly walking into the Sameal's light, his own form faded once more...

Bonus Action: Converting a 2nd level spell slot into 2 Sorcery Points.

Action: Belzo Casts (3rd level)Angelic Celerity on Samael, expending 1 Sorcerer Point to make the casting Subtle.
(DM Call on whether the material component factors as giving away the casting after the S/V portions of one has been eliminated, as one need only be holding a focus. If so, nevermind the use of the Metamagic)

Movement: Into the BURNING YET PROTECTIVE LIGHT!

End Turn: Blink(DC 11): 2.

"

(OOC: Belzo is able to subtly cast Haste.)

Strahd uses his first legendary action to swipe at Doremor with a claw attack.

Attack: 13 Damage: 18

Samael22,Hadrian22,Doremor21,Lair20, Hound of Ill Omen18, Fae16,Strahd13,Belzo10,Ismark9,Gertrude8,Emil5

Ismark is going to attempt to attack Strahd twice.

Attack: 15 Damage: 4

Attack: 10 Damage: 6

Samael22,Hadrian22,Doremor21,Lair20, Hound of Ill Omen18, Fae16,Strahd13,Belzo10,Ismark9,Gertrude8,Emil5

Both of Ismark's attacks miss.

Gertrude flies over to Strahd, helping the next person attack him before flying away as far as she can.

Samael22,Hadrian22,Doremor21,Lair20, Hound of Ill Omen18, Fae16,Strahd13,Belzo10,Ismark9,Gertrude8,Emil5

Gertrude helps! Strahd withholds his legendary actions for now!

Samael22,Hadrian22,Doremor21,Lair20, Hound of Ill Omen18, Fae16,Strahd13,Belzo10,Ismark9,Gertrude8,Emil5

Emil attacks Fae!

Attack: 5 Damage: 3

Attack: 17 Damage: 6

Samael is up!

Samael, hasten, glowing with radiant power, sunsword drawn and now assisted by Gertude, attacks Strahd. Casting [magic]Wrathful Smite[/magic] on his blade, allowing it's own sentient emotions to fuel the strike, he moves with speed to strike the vampire lord.

Attack 1: 23 Damage: 13 + 9 (Radiant Soul) + 26(if hit, Divine Smite(lvl3)) + 2(addition Radiant damage cause undead target (sunsword))
Attack: 13 Damage: 9 + 20(if hit, Divine Smite(lvl3)) + 3(addition Radiant damage cause undead target (sunsword))

(WIS save DC 17 for Wrathful Smite, if hits)
(if one strike doesn't hit, I'll take back the spell slot for the Smite)

(says potentially manipulated cause I added the extra 1d8 damage from the Sunsword in an edit, sorry. Let me know if you want me to reroll)

(addition rolls from 2phase of turn)

Hasted Attack: 29 Damage: 14 + 8(addition Radiant damage cause undead target (sunsword)) + 31 (smite)

Wrath Smite damage: 4 psychic

Samael's first and third attacks hit Strahd, who doesn't like that at all! He's going to use his second legendary action to move 30 feet away without provoking attacks of opportunity!

Wisdom: 17

Hadrian is up!