'Either their plan is so important that they can afford to sacrifice him or the undead know that such attacks can't kill the thrall.' Lith thought while taking his acorn out of the sealing box he had stored it into.

Undead couldn't use dimensional magic inside Laruel, but thralls could and he had no idea if there were others in the crowd if not even disguised among the angry mob. What happened next took him by surprise.

The thrall roared, emitting a pulse of darkness magic that combined with the raw strength of his shapeshifting body was enough to ward off his attackers. The leaves and bark had disappeared, replaced by a dirty brown thick fur that covered the entirety of what had been a Treantling just a second before.

The creature in front of them had a round head, with feral eyes as big as a saucer. It had bright red irises and vertical pupils that looked at the crowd with a mix of hate and spite.

Its maw was lipless and so big that it took all the lower half of his head. The mouth was filled with sharp, long fangs, each one about ten centimeters (4") long. All the damages the thrall had sustained were gone and his arms were now even more muscular than before, ending with razor-sharp claws.

"By the Great Mother! The spawn of a Grendel is not something plant folks can take. If we get surrounded, prepare to run." Kalla said while preparing for the fight. The thrall of a Grendel alone was already a tough opponent, but she was even more worried about what the other undead would do.

The plant folks did their worst, but air, water, and earth magic just bounced harmlessly on the creature's fur, nor any of their attacks left so much as a scratch on him.

The thrall laughed his heart out and then began to literally mow down his opponents, cutting through wood, vines, and flesh as if they were just paper mache.

"What's a Grendel?" Friya asked while unsheathing her weapon, quickly followed by Lith and Phloria.

"A very rare and dangerous undead. They are nigh-invulnerable due to their iron skin. Neither magic nor blades can usually harm them. Their only weaknesses are darkness magic and blunt weapons."

"What's the catch?" Lith asked. Grendels were considered barely more than a myth and the information about them in the bestiaries stored inside Soluspedia was centuries old. He trusted Kalla more than a collection of hearsay.

Also, there had to be a reason he had never heard about them. If Grendels were that strong, they wouldn't have gone almost extinct.

"They can't stand sunlight, can't use any magic outside of the darkness element, and they can't heal. A Grendel can only replace their wounded parts with healthy ones taken from their victims…." Kalla's reply was cut short by the thrall appearing in front of Lith with lightning-fast movements.

Even though Lith was already infused with all the elements, the creature was so quick that his claws managed to get past Lith's guard and aim at his heart. Kalla had no time to warn them that Grendels made up for their magical shortcomings with a physical prowess that rivaled that of veteran Emperor Beasts.

Yet the thing in front of them was just a thrall, not a real Grendel. The powerful blood core the Treantling's sire had gifted him with allowed Illum to borrow the form of a Grendel and some of its abilities, but that was it.

Otherwise being out during the day would have been fatal for him, nor the Treantling would have healed so easily from Lith's previous attack. Lith sidestepped the lunge and struck at the extended arm after infusing Ruin with as much darkness magic as he could.

The thick fur covering the arm sizzled and burned as the chaotic energies turned it pitch-black, but neither the spell nor the blade nicked the underlying flesh. The impact sent waves through the blade and Lith's arms, making him feel as if he had struck a rock.

'What the heck? If this is the durability of a thrall, how though is a real Grendel?' Lith thought while circling around the creature and forcing him to turn his back on the rest of the group.

The thrall surprised Lith once again, simply ignoring him and continuing to charge forward. The creature extended his left arm toward Kalla's head in another sudden attack.

His claws pierced through the thin layer of darkness protecting her physical form, clutching her skull and ripping it off her spine before any of her allies could react.

"This is going to leave a mark." The skull said while still trapped in the clutches of the thrall. The creature tried to get rid of the undying monster and throw the bear skull away, but it melted in his hand and revealed its real nature.

While Lith stood in front of her, Kalla had swapped places with her own shadow, giving it shape and substance by manipulating the darkness and light elements. What the creature had attacked was a huge mass of energy that had now marked him as its target.

The thrall shrieked as the darkness element seeped into his arm, eating away both the Treantling and the blood core empowering him.

'Wow. It's the first time that someone ignores me. Let's thank him properly.' Lith struck at the creature with his gravity infused blade multiple times, making the thrall's weight increase tenfold each time Ruin hit its mark.

Not even that managed to leave a scratch, but the sudden gravity variations threw the creature off balance, making it impossible for him to dodge the dark mass shaped as Kalla's body that was charging at him.

The thrall was more than strong enough to escape from the gravity pull, but when he attempted to dodge the living projectile, Lith removed the extra weight. The sidestep was performed with too much momentum, so the Grendel crashed against the nearest tree-house, forcing him to a halt.

The dark mass struck first, immediately followed by Phloria's and Friya's swords, both aimed at the open maw of the creature who was screaming due to the pain it felt. Darkness magic was corroding both the Treantling and the blood core fueling his transformation, greatly reducing the protection that the Grendel's life essence coursing through his body offered.

The blades only met soft tissues, piercing their way until they hit the skull and releasing their enchantments the moment they failed to penetrate the bone. The thrall started to spat out huge amounts of black and green blood from the gaping wound in his mouth.

A Treantling would have easily mended the damage, but the transformation did more than just enhancing his physical abilities. It also carried the curse of the Grendel, slowing his healing abilities so much that they were useless.

"Revert to your plant form and I'll call back the darkness energy. You have a lot of explaining to do." Kalla said, triggering the reaction of a couple of undead hidden amid the crowd.

They had been waiting the whole time for an opening, but neither Kalla nor Lith had let them out of their sight, and with dimensional magic sealed, the undead's options were limited.

Now their situation had just gotten from bad to worse. If Illum fell into enemy hands their master plan would be ruined. The only thing they could do was either rescue him or make sure that he wouldn't talk.