Strongest Side-Character System: Please don't steal the spotlight

Vonjo stood silently, staring at the ridiculous three-headed frog that sat before him like some confused, bloated totem of disappointment. 

It croaked once—awkwardly—as if sensing the sheer disdain wafting off him in waves. 

The demonoid creatures nearby still lingered at a distance, wary but not particularly interested anymore. 

The summoning circle had long faded into scorched ash, and the oppressive heat of the hellish realm returned to its usual simmering madness. 

Vonjo's crimson coat fluttered slightly in the sulfuric breeze as he rubbed his temples in disbelief.

"I killed a lot of demonoids for the system to summon this shit," Vonjo muttered, voice laced with deadpan sarcasm, as he gave the frog another withering look. "But whatever... I should've expected it. Not all System rewards are overpowered."

The bullet comments lit up instantly, their white and neon text flying across the air, visible only to Vonjo:

[MoonPie69]: LMAO, HAHAHA! VONJO, THE WEAKEST FROG SUMMONER IS BORN! 

[TearsOfTuna]: Didn't he say he sacrificed half a battlefield just to get a demonic plush toy? Lmao! 

[CursedRizzlord]: Haha, that thing can't even be used as a mount. What the hell! 

He ignored them. Mostly.

Behind him, Eugene stared at the frog and then at Vonjo, eyebrows twitching in mild confusion. 

He hesitated before stepping forward, his steps cautious and respectful, like a student speaking to a volatile master.

"Sir… how was the frog summoned?" Eugene asked, tilting his head slightly.

Vonjo scoffed, not bothering to look at him. "Don't ask me."

Eugene stood there awkwardly, casting a nervous glance at the three-headed frog that was now licking one of its eyeballs. 

Then, slowly, tentatively, as if unsure whether it was a trap, he asked, "Sir? Sir… sir Vonjo?"

Vonjo sighed, pausing mid-step, then glanced over his shoulder. "What?"

"…Are you just gonna leave it there?"

"Yeah," Vonjo said flatly. "It's useless."

Another pause. Then Eugene cleared his throat softly and said, "Um… c-can I have it?"

Vonjo turned around, raising an eyebrow. "Sure. Knock yourself out."

Without another word, Eugene jogged over to the frog and—much to Vonjo's growing interest—took out a small, black item from the inner lining of his coat. It glowed faintly with a sickly violet hue, swirling with threads of black curse energy. 

As he pressed it to the frog's middle head, the item disintegrated into mist and sank into the creature's slimy skin. 

The ground trembled faintly.

The frog's body pulsed with crimson veins as the summoning mark underneath it reignited. In the blink of an eye, a blinding white light engulfed it, the hellish air howling as if surprised. 

When the light dimmed, the frog had grown larger—about the size of a warhorse now—and something about it had changed. Its skin shimmered with spatial runes that glowed faintly under its warty surface.

Vonjo's eyes narrowed. Immediately, a mechanical ping rang in his ears—his System's voice cold and mechanical.

DING!

[Fallen Curse Evolution triggered—'Three-Headed Hell Frog' has evolved into a 'Spatial Frog'. Classification: Living Spatial Mount.]

[Warning: Mount previously discarded by the Host.]

Vonjo's jaw slackened slightly. "What the fuck…?"

Eugene flinched.

Vonjo quickly composed himself and masked his expression with a neutral one, pretending he hadn't just been blindsided. "...What did you just do? Why did it glow?"

Eugene looked down, trying to hide the flicker of guilt in his eyes. He cannot reveal that it's from his RPG bloodline ability treasure loot. "I—I just fed it a treasure… it was in my pocket. A rare one. And, uh… now it can store a lot of stuff. Like, uh… under my control."

Vonjo's eyes gleamed with a dangerous curiosity. "Really? Show me."

Eugene hesitated, then nodded and turned to the frog. "Open your mouth."

The center head opened its maw, revealing a strange void-like interior, as if the mouth led not to a throat, but to a spatial vortex.

Vonjo stepped closer, watching as Eugene carefully placed his archery gear inside—his longbow, his quiver, a small armor plate. Each item vanished into the frog's mouth without a sound.

Vonjo whistled low. "That all?"

"Not yet," Eugene said, and gestured.

The right head opened next. This time, he pulled out what appeared to be a blade, swung it into the air, and it disintegrated before returning to the mouth. "This head is for spatial weapons. Bound weapons. Once I feed it a weapon, I can summon it back in an instant. It registers the weapon to me and keeps it ready."

He opened the left head next. Inside shimmered a soft blue light, and as he pulled a hand out, a spiritual herb floated in the air. "This one… this is the storage for spiritual things. Like herbs, pills, anything with spiritual resonance. It preserves them too. Keeps their potency intact."

Vonjo blinked. Then blinked again.

The bullet comments were already going wild:

[FrogGod420]: THREE STORAGE HEADS?! WHAT THE FUCKING HELL?!

[InventorySenpai]: Eugene just speedran into becoming a one-man supply depot.

[NoSkillsJustLuck]: THIS GUY MADE A LIVING LOOTBOX!!! I'M SURE THIS VONJO GUY WOULD BE JEALOUS!

Vonjo took a step back, mouth hanging open for a beat too long before he covered it with a sharp exhale. "Jumping hellspawn… this frog is actually useful now."

"...Y-yes, sir," Eugene said, trying not to look too smug.

Vonjo's expression twisted with frustration and awe, his voice low. "What are the storage capacities? Each head. Tell me."

"Yes, sir," Eugene nodded. "The middle head—the general spatial one—can store about ten cubic meters. Think of it like a mobile room."

Vonjo nodded slowly.

"The right head—for weapons—only stores items that are spiritually bound to me. I can recall any of them in combat within a second. Max capacity is ten weapons."

"And the left one?"

"It stores a maximum of twenty spiritual items. And it has preservation functions. Nothing spoils, withers, or ages inside it."

Vonjo stared. "Can it be killed?"

"If the frog dies, the items won't be lost," Eugene said, quickly. "I've… tested that before. If the creature is made into a spatial vessel through my… treasure, it anchors the storage to the item. The system reclaims it through me. I can retrieve the stored things at any time—unless the item is forcibly destroyed by a higher being."

Vonjo stood there, eyes slowly widening. "Wait… you can do this to other animals too?"

Eugene's lips tightened.

Vonjo stepped closer. "You can… turn random animals into living storage tools?"

"Yes… sir," Eugene admitted, carefully.

Vonjo turned his back to him and let out a breathless laugh, quietly muttering, "This is insane…"

[SystemBroski]: THIS GUY'S AN ENTIRE LOGISTICS DEPARTMENT.

[RPGStorageKing]: Not MC, but MVP.

[VONJOGETWRECKED]: LMAOOO this is peak humiliation.

Vonjo snorted. "Tch, shut up," he muttered at the bullet comments—then, louder, "How about this…"

He turned back with a smile that was both sly and lazy.

"I'll take this frog back."

Eugene froze. "S-Sir?"

Vonjo grinned. "You know, it was my summon."

[GreedyPigVonjo]: Bro... not the unknown side character stealing his main character's mount!

[JusticeForEugene]: DON'T GIVE HIM BACK HIS FROG DAMMIT. HE ALREADY ABANDONED IT! 

But Vonjo didn't care.

He walked forward, eyes gleaming.

"A living storage… how convenient."