Morthos keeps an eye out, his Fey ancestry letting him see through the darkness. 

Perception: 15

(Lilandra perception 20, wow that was unexpected)

Morgan's eyes continue to scan the area, trying to eek what he can out of the dim lighting.

perception: 6

Thad looks about the area as he follows the others, trying to remain as quiet as possible with Lilandra's help (Stealth with bonus: 17; Perception: 9).

Surrounded by the hazy grey veil of Lilandra’s magic the group crept like ghosts up the lonely hill, leaving behind no evidence of their passing as they very carefully worked their way closer to the great stone monolith.

There was no shortage of cover, as the hill was littered with moss-covered boulders, thick underbrush, and large old trees. And despite the sunlight of a new day illuminating the top of the hill, everywhere else the thick foliage continued to shroud the area in darkness. It was eerie how the shapes of things around them blended together into a tangle of silhouettes. Even though such conditions would help conceal the wary heroes, it also did the same for everything else, too. For Thad and Morgan, it was all they could do to simply maintain proximity to the group and not lose their comrades in the shadows.

Leading the way, Morthos diligently scanned every detail he could with a fair amount of suspicion but could see no evidence of traps or even signs of activity. The hill appeared to be deserted. He did, however, notice a dark shape cast aside on the stone steps further up the hill, near the monolith – a large, ragged black cloak.

LILANDRA ONLY:

Morgan kept his angry curses to himself, he could barely see those he was traveling with, let alone any possible threats around them.

Seeing the crawling creature she freezes, trying to determine if it saw us. She will look towards Morthos but has no way of alerting him without making sound so she turns to Morgan and Thad who follow her and block their movement to point at the creature crawling above them. 

Once Lilandra has pointing out the creature and sees that Morgan or Thad saw what she was pointing at she turns to move towards Morthos again, trying to move at slightly faster pace than Morthos.
If she gets about 15ft distance from the creature she saw so it wont hear her, hoping no others are near.  With her voice as quiet as she can she speaks her spell and point to Morthos Let the air move against him casting Druidcraft to create a puff of wind directed into Morthos's face to be sure to catch his attention and halt his movement to allow Lilandra to catch up. 

As Morthos moves through thick foilage, he spots the black-robed shape. At the same time, he feels a puff of wind on his face coming from Lilandra. He halts and sees her moving at an accelerated pace, a bit spooked. She must have spotted something as well, but he wasn't sure if she saw the same thing he did. 

Morthos casts Prestidigitation and creates an illusory image on his hand, glowing words that read, "Halt. Lilandra sees something." He holds his hand up so his companions can read them through the darkness. He also draws his rapier and looks around for threats other than the black-robed shape. 

Perception: 16

[I should specify: By "a dark shape cast aside on the stone steps" I meant that the cloak is simply laying on the steps, abandoned, nobody inside it or anything. Morthos would likely not consider a discarded garment as a threat (although he might be, that's up to you). My apologies if that wasn't described clearly enough.

Also, since you've been alerted to the fact there is actually something to look for, you can make that perception check with advantage. (So make another one, and between it and the last one we'll use the better roll.]

(Alright, I was a little confused, but I get it now).

Perception:  20

Thad stops at Lilandra's warning and looks up towards the figure she pointed towards. His hand slowly moves towards his weapon, ready to draw it if need be, and his arm tightens its grip on his shield.

After Lilandra pointed it out to Thad and Morgan and then alerted Morthos with a clever puff of air, all were now aware of the creature’s silent presence. And as luck would have it, the same could not be said vice versa.

Crawling alongside a wide, low-hanging branch overhead, the human-sized insect continued its creeping advance with its ant-like head peeking under the branch, its wriggling antennae facing towards the stairs leading up to the monolith. Most likely thanks to Lilandra’s magical shroud, it appeared completely ignorant of the group immediately below it.

The thing circled to the top of the branch where it lifted itself upright and perched in place. Then, in mere moments, a wave of color washed over its chitinous carapace, shifting from a perfect match of the bark to a deep leafy green hue, which from this close distance provided a better contrast between its actual anatomy and what turned out to be, in fact, equipment. It squatted on its two hind legs, leaving four other appendages dangling at its sides. Crossed over its thorax were a pair of shortbows, and at each hip was a large rectangular covered quiver.

After sweeping its head back and forth to check its surroundings (everywhere, luckily, except straight down), the creature’s legs uncoiled like springs, propelling it seemingly effortlessly higher into the treetops where it disappeared.

[Very smart use of Druidcraft, Lilandra! For that I'll award you with Inspiration! Use it wisely!]

Morgan watched the... well thing... go up into the tree.  he had never seen such a being before, though it must be a person he supposed, with the equipment he had spotted it wearing.  Glancing to the others, who were still just dim figures in the darkness, he didn't dare speak, not knowing if there were others around them.  he hoped his companions could see better than he could, and gestured towards the path ahead, wondering if they should continue or not.

Seeing the creature move away from the group Lilandra sigh's with relief. Assuming they were not spotted yet. 

She did not speak yet but wanted to ask if someone knew what that was. It was certainly no creature she has ever seen before.

Lilandra will look around to see shapes of the others, still maintaining concentration to mask their presence . She will then start moving towards the monolith, once she reaches it she will position herself with her back against the wall waiting for everyone to gather before the stairs. 

During the walk she will try and keep an eye out for more creatures (perception 17)

Morthos watches warily and the insectoid creature leaps into the treetops. 

"What a monstrosity!" he thought. He hoped not to encounter more of those things, but considering they were getting closer to Gernacht's cathedral, he wasn't sure his wish would be granted. He stays closer to the path ahead as he scans for more threats. 

Perception: 20

Thad calls upon his Divine Sense as the creature goes to leave, trying to identify if it's celestial, fiend or undead, but it will also notify him of anything else in the area (60ft radius). Thad stroked his beard as he watched the creature move away. This does not bode well, he thought. He slowly moves forwards with others, trying to stay as quiet as his weight and armour would allow.

[CONSTITUTION SAVE - THAD]

Thad Con Save: 16

[THAD SAVE SUCCESS!]

Reaching out with his senses, the dwarven commander opened his awareness to the cosmic energies that permeated all of creation. He did so with the intention of perhaps identifying the elusive insectoid creature stalking among the treetops, but could not detect anything in the direction he witnessed it jump to. He did, however, sense something else entirely, something far more than perhaps any of them had bargained for. It was a fiendish presence no doubt, but the energy Thadraes felt was so immense and so powerful it slammed his consciousness like a brick wall!

[1 POINT PSYCHIC DAMAGE]

Not only that, but the energy was physically rising. From a point approximately 50ft underground, directly below the monolith (which Thad could also sense possessed its own desecrated aura), it was traveling upward at a rapid pace!

Meanwhile, despite being on alert that something else was on this hill with them, Morthos did not observe anything else amiss at present. Lilandra, as she advanced towards the monolith, was rewarded for her vigilance with another fleeting glimpse.

[LILANDRA ONLY:]

 With her back against the cool, mossy stone of the diabolical structure as she waited for the others to regroup, after a few moments she would notice the monolith begin to vibrate. These vibrations quickly escalated, noticeable to the entire party as a fully audible rumble as the entire thing began to shake!

Something was happening!

[STEALTH CHECKS AT DISADVANTAGE IF YOU ATTEMPT TO RAPIDLY RELOCATE]

At the last moment, Morthos dashes behind some trees as the entire monolith starts shaking. 

Stealth: 11 +10 Pass Without Trace