Ttharg Krixkrux
As the Grey Slaad takes a bite out of Ttharg, Ttharg retaliates by shouting back in the Slaad's face, his voice amplified by his faith into a thunderous assault on it's eardrums: "MAY YE SCALES ROT AND WITHER, BOTTOM FEEDER!" The Slaad seemed to dodge out of the way of most of Ttharg's tirade, but couldn't avoid all of it.
For a moment, Ttharg was concerned when the Red Slaad collapsed onto Fork, but then the valiant Kobold crawled out from underneath it's corpse.
He looked around at the crew, who all seemed to be in various states of injury, including himself. "Finish off this scaleywag! Hurry!"
They needed to finish off this foe quickly, and so Ttharg quickly holstered his Warhammer, repositioned himself around the Slaad, and reached out to the sky above the melee. "Bahamut, I call to ye! Strike me foe with your blessed lightning!" In an instant, a small storm cloud appeared above the battle and a electricity crackled within the cloud. Ttharg took out his holy symbol of Bahamut and proudly displayed it to the sky. As if in response, a bolt of lightning struck the ground next to the Slaad with a sound that defined Ttharg's lineage: krixkrux. Electricity arced towards the Slaad almost like a brilliant white claw reaching out for the creature; the power of which was increased by Ttharg's display of faith.
Ttharg then directed his Spiritual Weapon to attack whatever was left of the Slaad.
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Move Action to move around the Slaad, getting out of the way of the incoming Lightning Bolt.
Free Action to Holster Warhammer
Main Action to Cast Call Lightning (3rd Level Spell) centred just to the north-east of the Slaad so that it will only hit it. Grey Slaad needs to make a DC 13 Dex Save or take 3D10 Lightning Damage. Takes half damage on a success.
Grey Slaad Dex Save = (1d20)[20]+mods vs DC 13.
Regardless of whether the Slaad succeeds it's saving throw, Ttharg will use his Channel Divinity to deal maximum damage to it. So 30 Lightning Damage or 15 Lightning Damage depending on it's save.
Bonus Action to direct Spiritual Weapon to attack the Slaad: 21 to hit for 9 Force Damage.