OOC: I assume that passes. Gonna do what I would've done earlier if I hand't failed the save:

Threlan looks at the gnoll next to them, and smiles. A cruel smile Veldruk would shiver at the sight of. It is the smile of a drow priestess about to inflict pain. and enjoy doing it.

Threlan whispers something in elvish as she casts hold person. The gnoll must make a DC 14 wisdom save or be paralyzed for 1 min. It can repeat the save at the end of each of its turns.

Threlan cackles with glee at the (hopefully) helpless hyena-man, and looks at Veldruk "Stick 'em." She says as she gives him a bardic inspiration (+ 1 to next attack roll, ability check, or save)

Edit: I forgot to change a few details, so I'm editing this post. It will reroll the bardic inspire die, but its fine. the original role was a five.

Nodjeim manages to wiggle the ladder free from the stone being used to keep it in place and lifts it up, he still has a bonus and move action, if he would like to use them. 

With a sound like a xylophone's unfortunate meeting with a seven ton boulder, the skeleton Olan aims at falls to pieces. Olan is not hidden to the ordinary gnolls, but the undead and the ogre have no idea where he is.

Threla manages to recover, and casts a spell on the gnoll, locking its limbs. Unfortunately, this gnoll seems to be blessed by Yeenoghu himself, as they succeed the save despite only having a +1 bonus. 

The gnoll nearest Nodjeim attempts to climb the sheer hillside. Rolling a natural 1, I'm going to say that it actually does manage to get almost to the top before a handhold crumbles and it tumbles down, taking 2 falling damage. It then drops its spear as a free action and uses its object interaction to draw a plundered bow and fire at Nodjeim. Its arrow flies into the cliffside and snaps in half. Meanwhile, the other ordinary gnoll stands up from the corpse it's been gnawing on and draws its bow, shooting at Nodjeim as well. It misses as well, and runs toward the cliff.

The skeletons all dash and move towards the foes they can spot.

Finally, the ogre emerges from the smashed-out front door of the house he was occupying. He looks around and, seeing that Chakka is the closest and cornered, fires a bolt at the bug. Being a not-so-dextrous ogre, he has some trouble with the trigger mechanism, and Chakka manages to duck out of the way as rubble is sprayed into the air above them. Where their head was just a second ago, a massive bolt sprouts from the stone wall.

Evelyn, Veldruk, go!

Map:

((No BA of movement for Nodjeim, he's basically waiting to see if they try climbing up so he can scramble to them and try to push them right back down...))

Evelyn scans the battlefield, seeking to do the most damage possible. She summons another blast of thunder, centering it as to catch as many gnolls as possible in the blast (within 60 ft of her location).

Damage - 20

Evelyn can unfortunately only target two creatures, and I tried. Would she like to target the gnoll and witherling by the ladder, the gnoll on the ground or one of the zombies (either one), the ogre and the zombie closest to it, or the ogre and the witherling closest to it? 

(I'll target the ogre and the zombie!)

The thunderous blast doesn't seem to occupy the zombie as harshly, but the ogre is nearly knocked over by its force, blood running from its knobby ears. 

Veldruk, you're up! Stop rolling like shit!

When his strike missed his thoughts turned to Darkness. The spell should suppress the effect of the sun and blind the enemies. The problem, he noticed rising his shield and blocking an attack, was that it would incite the gnoll to move away from him and closer to the full casters. Worse yet, were he to become too hard of an enemy, his allies could have to deal with concentrated fire.

Veldruk cursed under his breath as Threlan words seemed to give him strength. His body felt lighter, his mind sharper. Let’s try not wasting it, he said on his head remembering the time when they were ambushed. The time when he could not make good use of Invisibility. Concentrating on his blood, drawing energy from it, he channeled magic through his steel. As an arcane word was whispered his sword glowed. Four globules of light jumped from it, taking place ten feet from one another. None bigger than a torch, all dimming the clarity around it.

To his eyes the relief was immediate. Now it should be easier to hit. And not only for him. The bard would have an easier time too. And you should keep trying to cut me. He opened his guard to the gnoll, hoping the creature would jump at the chance of landing a blow.

 Notes: Let's be honest, to be shit my rolls have to improve a great deal. Veldruk uses his action to cast Dancing Lights can't roll terribly if you don't roll.

(OOC: for the others, veldruk's dancing lights convert all light to dim light in their radius. Magic!)

Four shimmering globes of twilight are conjured into the air, plunging the majority of the party into a moon-bathed half-darkness. Both Veldruk and Threla are finally able to see properly, as the light of the sun is dimmed. Threla can definitely note that this is atypical of the spellcasting abilities granted to most drow.

The zombies shamble forward on their turn.

Meanwhile, checking Veldruk's deception against the gnoll's insight to see whether or not it believes that his guard is down (I would allow you to actually put your guard down if you like, granting advantage, but I'm assuming you'd prefer not to give the gnoll free advantage). The rolls equal, but due to the gnoll's bloodlust it's going to jump at the opportunity anyways. It attacks Veldruk twice, but the warrior can reflect the blows with almost lazy ease. No amount of gnollish ferocity can equal his defensive mastery. We won't mention offense. 

Chakka lands two hits on the skeleton in front of them, but their damage output is honestly kind of terrible. It remains standing, though barely.

Olan, Nodjeim, Threla, you're up!

Map: (it's just getting more and more vertical with every round) (I placed the lights in the areas that seemed most likely for combat to take place/enemies for stand, you can move them on your turn with a bonus action anyways)

Olan moves towards Chakka's position, looking for a better line of sight to the ogre. Once in position he takes careful aim and sends one of the barbed arrows at the beast, hoping to slow it down. Once released he moves on, again keeping to cover where possible. (Heading up the map towards the others).

Attack Attack: 21 Damage: 10

Stealth 21

     Nodjeim takes a brief moment and focuses his thoughts and sends all his energies.  He blinks quickly and then appears to start shadowboxing or going through his kata except that when he throws a punch there is a radiant bolt of energy released at the end of the punch that flies down towards his opponents.

Radiant Sun Bolt Attack:  12 to his for 9 radiant damage

     Then a Ki point spent to Furry of Blows with this attack

Flurry of Blows Sun Bolt Attack 1:  26 to hit for 6 radiant damage
Flurry of Blows Sun Bolt Attack2:  Nat 1...

Olan should have had advantage due to being hidden, since the roof is low enough that he can hide while the brush still provides enough cover with Olan's disguise to hide him. Checking for a crit and rolling sneak attack... rolled an 11, youch. The ogre howls in pain, anger, and a bit of fear. It's heavily bloodied.

Flipping a coin for whether Nodjeim targets the gnoll or the witherling... witherling it is. It blows up. Radiant light scorches it to a crisp, the little dried flesh still clinging to its bones curling and bubbling.

Threla, your go! You can actually see!

Map:

Threla looks around, her eyes finally taking in the full extent of the terrain

She looks at the gnoll next to her and leans in, whispering in its torn and ragged ear as she casts dissonant whispers on it. It must make a DC 14 wisdom save. (hopefully it doesn't succeed)

On a failure, it takes 8 psychic damage and must use its reaction to move as far as its speed allows away from you. The creature doesn’t move into obviously dangerous ground, such as a fire or a pit.

On a success, it takes half as much damage and doesn't have to run. Since the creature is using its movement to run away, it would provoke an opportunity attack from Threla and Veldruk (She hits it with her rapier. 11 to hit, 8 damage)

Man. I'm sorry. The gnoll rolls a 19, for a total of 20. This thing is blessed.

The rest of the gnolls go! The one at the base of the cliff picks up its spear in one hand and attempts to climb up the cliff. It manages to get up, and so drops its bow and wields its spear in two hands as a free action, then stabs at Nodjeim. It misses because obviously. The one down below fires again with its bow while approaching. It misses. 

The two remaining witherlings converge on Chakka, one climbing over the corpse of its comrade to swing a spiked club at the thri-kreen's carapace. Neither attack connects. 

Finally, the ogre looks up at where Olan once was, sees that he is gone, and so turns to Evelyn, the other one who has damaged him. He looses another bolt, and surprisingly connects with the unarmored mage! Evelyn takes 22 points of piercing damage as the bolt slams into her, almost knocking her unconscious in a single hit! The ogre then yells out in pain as the recoil shudders through its body, causing its wounds to ooze yet more. It ducks inside the house, yelling something. Olan and Nodjeim both hear the phrase, since Nodjeim is close and Olan's passive perception is good enough. "They not bring new bodies, bad doggies lied! Aauuntiee!!" And then it is inside.

Evelyn, Veldruk, you're up!

Map:

Somehow Evelyn manages to stay conscious. With her last bit of energy left, she unleashes another spell toward the bunched up gnolls, another blast of thunder. If she is able to, she will limp toward anything that would provide cover.

Damage - 11

(Dice roll got messed up. Original damage total was 12.)