Hearing Erik's words, Sebastian nodded to them and turned into black smoke, rushing out swiftly in Phase Form.

Watching Sebastian leave, Erik said to Charles, "Charles, now it's up to us. I don't want to be outdone by Sebastian too much.

I'll take the front and hold the pressure.

You stay back, coordinate, and give orders. Together, we'll deal with these damned Sentinels!"

Sebastian wasn't worried about Charles and Erik.

If over fifty skilled mutants couldn't wreak havoc here, they might as well abandon their planet. Sebastian would happily take them to his world to settle down instead.

Bang!

Sebastian waved his wand, casting Reducto, blasting a door open.

Seeing the instruments and computers inside, he didn't hesitate.

He waved his wand again, destroying them all with more Reducto blasts. Fortunately, to keep their location hidden, the facility hadn't connected to external networks, using only a local network.

Perhaps they never imagined the underground institute could be destroyed.

In their view, it was impenetrable. This made things easier for Sebastian.

Destroying the computers and instruments here would end the threat once and for all.

Of course, Sebastian didn't believe there were no backups.

But with the President under his complete control, restarting the Sentinel program would be nearly impossible.

Sebastian had countless ways to stop it.

Plus, the mutants wouldn't stand idly by. No matter how many backups existed, destroying this place and rooting out the Debarli aliens would mark the end of the Sentinel program.

Boom! Boom! Boom!

Sebastian cast Reducto repeatedly, red light threads striking instruments and computers, triggering explosions that soon engulfed the area in flames.

Sebastian continued as black smoke in Phase Form, moving forward. After demolishing several labs and server rooms, he faced the institute's first resistance.

Four Sentinels and at least thirty soldiers vaguely surrounded him.

Glancing at the soldiers' weapons, Sebastian looked at the Sentinels and smiled. "If this is all you have, you can't stop me. I heard there are original Sentinels here, far superior to regular ones—your ideal Sentinel model. Can I see them?"

Hearing Sebastian's words, the soldiers' captain snapped, "These are enough to deal with you. This is just the mutants' final struggle. Soon, we'll upgrade the Sentinels, and that'll be your doom!"

"Sorry, I've said many times, I'm not a mutant," Sebastian replied.

"Ridiculous! Not a mutant? Are you human then?" the captain scoffed. "Sentinels, kill this mutant!"

"Warning: Target is not a mutant. Proceed with attack?" the Sentinel queried.

The captain and soldiers were shocked, staring at Sebastian in disbelief. "How is this possible? If he's not a mutant but human, how does he have those incredible powers? A human? Impossible!"

Despite his disbelief, the captain ordered the attack.

The Sentinels charged at Sebastian, while the thirty-plus soldiers opened fire. Bullets and rockets whistled, pouring toward him.

Bang!

Sebastian's body burst into black smoke, activating Split Form, scattering into countless streams.

The Sentinels tried to track him, but Sebastian's form appeared on one Sentinel's shoulder.

His wand slashed, casting Sectumsempra. An invisible blade sliced the Sentinel from head to chest, splitting it in half.

Zzzzt!

Boom!

The Sentinel exploded. Sebastian, as black smoke in Phase Form, darted around, his wand flicking red light threads with Reducto, causing explosions.

The heavily armed soldiers were no match for his magic, suffering heavy casualties.

A piercing sonic wave rang out, chasing Sebastian with sweeping blasts.

While one Sentinel sustained the sonic attack, the other two transformed their hands into spears, pursuing him.

Bang!

One Sentinel's attack shattered a wall's water pipe, spraying water from the crack.

Sebastian pointed his wand, casting Aguamenti. The water surged, twisting into python-like ropes, binding the two pursuing Sentinels.

The water pythons tightened, and the Sentinels' bodies creaked.

Crack! Crack! Crack!

The two Sentinels' surfaces quickly turned to diamond skin, breaking free from the water snakes' stranglehold and charging at Sebastian.

In diamond skin mode, Sentinels could ignore most attacks, and Atlantean cum hogwarts water magic had little effect on them.

Sebastian raised his left hand, the Ring of Harnessing Power glowing. He clenched his fist and swung forward, unleashing a powerful shockwave that blasted the two Sentinels and the remaining living soldiers outward, crashing them against the walls.

At the same time, Sebastian slowly raised his wand. A mark symbolizing hellfire's authority appeared on his brow. Torrents of hellfire erupted from his wand, surging like living creatures toward the Sentinels and soldiers.

Sebastian hadn't planned to use hellfire. Its high energy cost aside, its overwhelming power, especially when fully unleashed, was too dangerous in the confined underground institute. The hellfire's terror would be fully unleashed.

Above the institute lay a major city.

If hellfire leaked, the damage would be worse than a hundred mutants combined.

Even with Sebastian controlling the President, mutant-human conflicts would have no chance of easing if that happened.

So, though Sebastian used hellfire, he was extremely cautious, carefully controlling it into streams of living flame, targeting the soldiers and Sentinels.

The flames instantly consumed all the soldiers, while the Sentinels, relying on diamond skin, barely held on.

But at that moment, a crimson beam shot from the hellfire, aiming straight at Sebastian!

Protego!

Buzz!

A slowly spinning, translucent circular shield appeared, blocking the crimson beam.

Sebastian saw a Sentinel, surrounded by an invisible barrier, step into the hellfire. Its appearance differed slightly. Ignoring the other three Sentinels melting in the flames, it rapidly approached him.

No doubt, this was the greatest obstacle: an Original Sentinel!

Emerging from the hellfire, the Sentinel's invisible barrier vanished. Its face split into four parts, firing a crimson beam at Sebastian, nearly identical to the abilities of Havok Alex, Cyclops Scott.

The Protego Seraphim Shield shifted, blocking the beam, rendering it ineffective. But the Original Sentinel didn't stop. Red flames surged from its body, gathering on its split head, unleashing a thicker crimson beam at the shield.

Sebastian squinted at the Sentinel behind the red light, flicking his wand. The Protego Seraphim shield tilted, deflecting the beam at an angle.

Simultaneously, Sebastian thrust his wand, casting Incendio. A molten energy bolt, like lightning, shot out, striking the Sentinel's chest, blasting it backward into the wall. Dispelling the shield, Sebastian waved his arm, casting Conjuro.

Metal tendrils sprouted from the floor and walls, binding the Sentinel's body.

But then, the Sentinel's body radiated intense heat, burning like a star. The heat melted the tendrils instantly. Its body, partly made of Adamantium, functioned normally in the temperature.

The Sentinel stretched out its hands, firing blazing flames. Sebastian ignored them.

Hellfire swirled around him, absorbing the flames upon contact, making them vanish.

Charging his wand, flames gathered swiftly.

Sebastian swung his wand forward, launching a highly compressed fireball, infused with hellfire and the Sentinel's flames. Its power was immense.

But before it hit, the Sentinel vanished in red mist, reappearing nearby.

Sebastian had anticipated this. The fireball, controlled by him, arced as the Sentinel reappeared, striking it and exploding violently.

Boom!

The Sentinel's massive frame flew backward, but as it hit the ground, its body morphed into a beast-like humanoid. Claws sprang from its hands and feet, gouging the floor. It charged at Sebastian like a shadow.

Sebastian waved his wand, casting Conjuro. Walls rose from the floor and sides, blocking the Sentinel. But it was fast and agile, its bulk no hindrance, attacking from all directions and angles.

Bang!

Despite his defenses, the Sentinel's claw struck Sebastian's chest, shattering his Protego armor, leaving five bloody gashes.

Rolling twice on the ground, Sebastian stood, waving his wand with Reparo to heal his wounds. Facing the beast-like Sentinel charging again, he raised his left hand. The Space Stone glowed, erecting an invisible spatial barrier, enclosing the area.

Then, the hellfire mark on Sebastian's brow emerged, no longer faint but blood-red, nearly black. With a slight wand flick, using Incendio, unweakened hellfire erupted from the void within the Space Stone's barrier. In an instant, the space became a true hell. Everything within melted and sublimated, vanishing in the flames.

Only Sebastian and the diamondized Sentinel remained.

Even the diamondized Sentinel's body sublimated bit by bit. Unable to fly in diamond form and with no foothold in the hellfire's power, it struggled futilely.

As its diamond skin vanished, its body melted completely, sublimating in the hellfire.

Having defeated the Sentinel, Sebastian waved his wand, drawing the hellfire back into his body, dispelling the spatial barrier.

Only then did he notice a massive spherical void in the institute, where everything had been consumed by hellfire.

"Phew…"

Without the hellfire's protection, the residual heat in the sphere could have roasted Sebastian instantly. That move, using the Space Stone and hellfire, had eradicated the Sentinel, but it drained him terribly.

His magic was nearly depleted, and the mental strain of controlling hellfire and space left him as exhausted as if he'd stayed awake three days.

If he were in an empty place, he could unleash hellfire fully without trouble. But in Washington's underground, reckless use would not only destroy the Sentinels but also erase Washington from the world.

One Original Sentinel was this tough. Two more would push him to his limits.

As Sebastian thought this, another Original Sentinel's hand emerged from a nearby corridor corner, gripping the wall, slowly stepping toward him!