It must be said that the sheer might displayed by the Burning Legion during the War of the Ancients caused many of Azeroth's denizens to overestimate the power of Fel energy.
As one of the six fundamental forces of the universe—alongside Light, Void, Arcane, Nature, and Death—Fel energy is unique in its expression, but it essentially remains on the same hierarchical level as the others.
The advantage of Fel lies in its ease of mastery and sheer destructive potential, but its flaws are equally glaring: those with weak wills can easily lose themselves in its chaotic nature, falling into a state of no return.
As a former member of Azshara's advisory council, Xavarian's Arcane talent and strength were beyond doubt. However, after being transformed into a Satyr—half-elf, half-demon—his blind worship of Fel led him to abandon his most proficient field. Instead, he chose the Warlock's Demonology specialization, focusing on summoning and empowerment.
His choice was incomprehensible to Andreas. Logically, a rational person would still choose the combat style that suited them best even after switching their source of energy, much like Illidan had done. Yet, Xavarian had done the exact opposite.
Putting aside the peak strength of a Demonology Warlock for a moment, the direct portal from Azeroth to the Twisting Nether had long since been closed. In the past, to protect the infinite potential of the world-soul within Azeroth, the Pantheon had specially placed defensive wards around the planet.
The Old Gods had only managed to infest the world because they arrived first, discovering Azeroth's location and embedding themselves before the Pantheon's arrival. Otherwise, they would be just like the Burning Legion: aware of Azeroth's existence but unable to lock onto its exact coordinates due to the illusions cast by Norgannon the Dreamweaver. The Legion could only sneak in when someone inside the planet actively sought death and opened a way.
After the explosion of the Well of Eternity, Azeroth's defensive barriers returned to normal operation. Aside from low-to-mid-tier demons scattered through space, demons of Mannoroth's caliber could no longer enter Azeroth at will, let alone Archimonde or Sargeras.
Xavarian had managed to call forth a variety of demon types: Succubi, Imps, Voidwalkers, Infernals, and Felguards—even the Doomguard he was currently channeling. However, all these demons shared one common trait: a lack of individual strength.
While Xavarian focused all his efforts on summoning the Doomguard, his other demons followed his orders, doing their best to entangle Andreas and prevent him from interrupting the incantation.
Clang!
With a casual horizontal slash, a Voidwalker—which Andreas used to call a "Blueberry"—was sliced apart by Shadow energy. Its body of pure energy immediately split in two and dissipated on the spot.
The weakest of the bunch, the Imps, fared even worse. Andreas fired a snap-shot Shadow Bolt, and the cunning little demon simply rolled its eyes and collapsed to the ground, playing dead.
"Just a bunch of rabble..."
Chanting his spell while moving, the black sphere of a Collapsing Star sucked in the relatively stronger Felguards and the Succubi who were posing and casting Seduction from a distance. Once the second stage of the spell's damage erupted, the low-to-mid-tier demons on the field were essentially cleared out.
However, their stalling had served its purpose. Xavarian's summoning ritual was complete. He raised his hands, glowing with sickly green Fel light, and roared, "With a living soul as the guide, come forth! Kaz'rogal, Lord of the Doomguard! Crush these fragile mortals!"
In response to Xavarian's strenuous summoning, a spatial rift appeared in the air above the battlefield. A pressure slightly stronger than that of a Dreadlord emanated from the crack.
Andreas's brow twitched slightly. He hadn't expected that Xavarian, by putting his very life on the line, could actually summon a high-ranking commander of the Burning Legion. To summon Kaz'rogal, Xavarian had forcibly sacrificed four powerful Satyrs standing near him.
No one wanted to be someone else's stepping stone. As the four Satyrs were turned into withered husks, the remaining Satyrs around Xavarian scrambled away from him.
As the spatial rift expanded and half of Kaz'rogal's body emerged, the triumphant Xavarian stared at the sky and laughed maniacally, completely ignoring his exposed back now that his guards had fled.
"Rawr!"
A fierce black panther suddenly pounced from the shadows. Its sharp claws collided with Xavarian's Fel Armor. Fel-green light of similar shades clashed violently, but the ambusher eventually gained the upper hand, and the demon armor shattered under the panther's strike.
As the panther pinned Xavarian to the ground from behind, its sharp teeth sank deep into his neck. Foul-smelling blood sprayed everywhere amidst Xavarian's terrified screams.
Andreas didn't bother with Xavarian, who had basically lost all combat capability. With his neck bitten and the panther's claws dug deep into his flesh, the intense pain made it impossible for Xavarian to calm down and cast spells—the Fear spell he might have used to save himself was out of the question.
Andreas turned his attention to the rift in the sky. With the supply of mana from Xavarian interrupted, the demon—who was twice the size of a normal Doomguard—found himself in the awkward position of being stuck halfway through a spatial rift that wasn't wide enough. He couldn't retreat, and he couldn't squeeze through.
Andreas had a vague memory of the name Kaz'rogal. Although he couldn't recall exactly what the demon had done, he was at least a somewhat famous figure within the Burning Legion.
Fel wasn't the only power capable of tearing through space; Arcane and Void could do the same, and vice versa.
While Kaz'rogal struggled desperately in the rift to free himself, Andreas extended both hands, holding them parallel to the spatial opening. As a purplish-black glow lit up his hands, he slowly brought them together. The spatial rift reacted in tandem, the exit being compressed smaller and smaller.
As the rift began to close, Kaz'rogal turned from surprise to fury. He shouted at Andreas with blustering bravado, "Mortal! Cease your insolent offense! I am the mighty Kaz—"
Snap!
The moment Andreas's hands finally met, the spatial rift snapped shut. Kaz'rogal's body, which had been protruding from the rift, was severed clean in half.
The powerful life force of a demon ensured that Kaz'rogal didn't die immediately even after losing half his body. He dragged himself across the ground, trailing internal organs and green blood, staring deathly at Andreas as if trying to etch his face into his soul.
"Mortal! I will remember this debt! One day, I will—"
Hum!
Andreas wordlessly used the light-blade of the Staff of G'Hanir to take Kaz'rogal's head.
"Too much chatter. Talk to me the next time you see me."
With the theatrical death of Xavarian's final reinforcement, the morale of the Satyrs, who had completely lost hope for a counterattack, hit rock bottom. They ignored Xavarian, who was still screaming and cursing under the panther's claws, and after throwing a few feints at their opponents, they fled into the mountains surrounding the Shas'ari Canyon.
Crunch!
After struggling for a long time, Xavarian's last layer of demonic skin was torn away. The panther bloodily bit his head clean off, and the screaming finally ceased.
"Ptui! Disgusting, foul blood."
The panther spat out the Fel-tainted blood with a look of utter disgust. Under Andreas' amused gaze, the beast shifted back into its normal form.
This Druid was none other than Andreas's long-time friend, Fandral Staghelm.