The abomination is able to resist the horns again. 

Abomination Wis Save

11

Abomination Con Save vs posion

25

9

The abomination is poisoned 

"We're really in this now," says Henry. locked in melee with the creature.

Thunder Gauntlets: on hit, the target has diadv on attacks except against me until the start of my next turn.
Attack: 23 Damage: 5
Attack: 7 Damage: 10

Abomination Recharge

3

The abomination lets out a roar of unfettered anger and its skins cracks even more releasing a halo of fire around its body. 

The creature activated Fire Blood

Whenever a creature within 5 feet of the abomination hits the abomination with a melee attack that deals piercing or slashing damage, that creature takes 3 fire damage

Abomination continues to attack Henry with disadvantage due to poison

Claw

Attack: 21 Damage: 7

On hit 4 fire damage

Claw

Attack: 10 Damage: 10

On hit 4 fire damage

The abomination is a tad bit more injured than moderately injured

Round 10

Post when able 

Modoc roars in its face and attacks recklessly again.

Attack: 15 Damage: 9

Attack: 19 Damage: 10

He'll take 3 fire damage from each hit.  And use his hammering horns again to try to force it out the window and into the river.

*Took off 3 fire damage assuming only the 19 hits.

Poking it seems like a bad idea so Gaelan strikes with his fist and foot.

Palm strike Attack: 19 Damage: 7

Knife hand Attack: 14 Damage: 4

Snap kick Attack: 17 Damage: 10

"It doesn't seem to want to go out the window!"

** The creature and Eirikur can make a CON check at the end of their turns to remove Poison condition but will have to make more CON saves it Gaelan hits it again.

Poisonous Skin

Any creature that grapples you or otherwise comes into direct contact with your skin must succeed on a DC 12 Constitution saving throw or become poisoned for 1 minute. A poisoned creature no longer in direct contact with you can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.

You can also apply this poison to any piercing weapon as part of an attack with that weapon, though when you hit the poison reacts differently. The target must succeed on a DC 12 Constitution saving throw or take 2d4 poison damage.

"Gloves, Gaelan. That's what I wanted to say earlier... Glove up your healing hand." Stomach still reeling, Eirikur repeats the spell.

OOC: Toll the Dead. Wis save 14 or 23 necrotic damage. Also, I finally made my Con save! No more poison!

(Waiting for Henry) 

Abomination Wis Save

11

Modoc's 19 did indeed hit 

[[I apologize for my absemce, I don't really have an excuse,]]

Thunder Gauntlets: Attack: 20 Damage: 7
Thunder Gauntlets: Attack: 16 Damage: 9

Bonus Action: Armor Defensive Field, 5 temp p.

Abomination Recharge

3

Abomination Con Save vs poison

8

The abomination reels from the barrage of attacks.

It lashes with attacks against Henry

Claw

Attack: 24 Damage: 5

On hit 2 fire damage

Attack: 18 Damage: 6

On hit 

5 fire damage