The arena: Monster killers.

The gob shoots an arrow at Yoku and misses with a 13. Nadir is up!

Nadir attacks the giant wolf spider that fights Dolrik.

Attack: 3 (bless) plus 21 Damage: 9

Attack: 2 (bless) plus 10 Damage: 2

(Marking it too I expect?)

 Those hit. It bites at you with a 7 to hit. 

The gob gang member shores his light crossbow at nadir with a 16 to miss. 
Ghilda casts cure wounds on herself, regaining 7 hit points. Yoku is up!

Why won't you die!

(Hunter's Mark, maintain concentration on the Gildha Duhn)

Attack Gildha Duhn, Longbow , bless, Hunter's Mark, Colossus Slayer: 4 (bless) + 14 Damage: 19

Quote from Smoke_and_Oakum >>

(Marking it too I expect?)

 Right, forgot to mention that. We can just assume that Nadir will mark everything she hits.

And she goes down. Count is up! (Don’t forget to track your ammunition)

Count seeing the flurry of attacks from the whitherlings goes for a Green-Flame Blade against the one bathing Sir Spitz:

Attack: 21 plus bless 2 Damage: 5

4 fire dame to the Grey flyer if hits,

Sir Spits to dodge

Does not hit. First Groll bite at Spitz: 19 to hit for 5 damage (with DA from shielding) club at Spitz: 15 to hit for 5 damage. 

second Gnoll at Count: 20 for 6 damage and 14 for 5

Scavver flies to nadir: 25 to hit (crit) for 15 damage. 
Dolriknis up!

Quote from Smoke_and_Oakum >>

And she goes down. Count is up! (Don’t forget to track your ammunition)

(Yoku has 13x arrows remaining in his quiver. Additionally, he has been maintaining concentration for 7 rounds.)

Gray Scavver, Toll the Dead.

DC14 Wis Save or 6 necrotic. (In game log)

Nadir reacts with Silvery Barbs to the crit, hopefully diverting the attack entirely.

Rerolled attack is a 14. Scavver save is a 3 and it goes down. 
Goblin makes a shortbow attack at Tokyo. 21 to hit for 3 damage. Nadir is up!

Nadir tries to finish the Giant wolf spider and if successful goes after a gnoll with her dagger.

Attack: 1 (bless) plus 17 Damage: 8

Attack: 1 (bless) plus 23 Damage: 2

The second attack finishes he spider. The gang member shoots at Nadir. 24 to hit for 8 damage. You is up!

(Concentration save from 3 damage, DC 10, with bless: 2 (bless) + 22, total: 24

(bonus action to move Hunter's Mark to the first Gnoll Witherling, concentration)

Attack first Gnoll Witherling, Longbow , bless, Hunter's Mark: 3 (bless) + 8 Damage: Unable to parse dice roll.

Seeing Nadir take a massive hit from the Goblin Gang Member, Yoku drops his bow (as a free action), then moves to engage the Goblin Gang Member (drawing his Rapier as part of his movement), so that he ends his turn adjacent to the Goblin Gang Member with Melee Finesse Weapon drawn, ending his turn.

That drops the first gnoll. Count is up!

Unfortunately I think the gnoll gets an attack after being brought to 0 hp...

Counts actions might change based on the outcome of that attack