Level: 10 (Synergy Penalty Active)
⸻
1:18 AM — Rooftop
Zack felt hollow.
Not weak.
Not injured.
Drained.
Synergy overuse had left a faint instability inside him.
Regeneration still worked.
Movement still sharp.
But energy flow wasn't smooth.
He closed his eyes.
Focused inward.
The system responded clearly this time.
SYNERGY CAPACITY: 5 SECONDS
ENERGY TOLERANCE: LOW
OVERLOAD RISK: HIGH
So that's the limit.
Five seconds.
And pushing it caused collapse.
He didn't curse.
He didn't get frustrated.
He understood.
Capacity must increase.
⸻
Kael's Diagnosis
Construction site.
Kael stood across from him.
"You tried to extend borrowed skill without base structure," Kael said calmly.
Zack nodded.
"How do I increase capacity?"
Kael answered immediately.
"Endurance under sustained mid-tier pressure."
"Meaning?"
"You must survive longer exchanges without synergy."
So that when synergy activates—
His body doesn't crash.
Makes sense.
⸻
Endurance Training
Kael didn't spar lightly this time.
He pushed.
Sustained combinations.
No breaks.
No resets.
Two minutes straight.
Three.
Four.
Zack blocked.
Dodged.
Compressed guard.
He got clipped.
Bruises formed.
He delayed regeneration.
Forced body to endure impact longer before healing.
Energy management.
Five minutes.
Breathing heavier.
Still standing.
Kael increased pressure.
Level 27 movement speed.
Not full strength.
But fast.
Zack stumbled once.
Recovered.
Didn't panic.
Six minutes.
Seven.
Kael stopped suddenly.
Zack almost fell to one knee.
Didn't.
"Good," Kael said.
Zack's chest rose heavily.
"That's it?"
"No."
⸻
Controlled Synergy Attempt
Kael stepped back.
"Now trigger it."
Zack nodded.
They engaged again.
Kael increased speed further.
Zack bit his shoulder lightly during close exchange.
Heat surged.
Synergy activated.
Movement clarity spiked.
But this time—
Zack didn't try to dominate.
He used it sparingly.
One clean dodge.
One precise counter.
Then he disengaged before the five seconds expired.
He cut it off voluntarily.
Heat cooled.
He didn't crash.
He didn't collapse.
Message appeared.
SYNERGY CONTROL IMPROVED
CAPACITY STABILITY +15%
Zack exhaled slowly.
That felt different.
He didn't burn out.
⸻
System Update
SYNERGY CAPACITY: 6 SECONDS
ENERGY TOLERANCE: MODERATE
One second increase.
That's it.
No flashy jump.
Just one second.
But that second matters.
⸻
Kael's Warning
"You are thinking correctly now," Kael said calmly.
"But remember."
Zack looked up.
"Capacity is not just time."
"What else?"
"Emotional stability."
Zack understood immediately.
If he triggers synergy in rage—
He'll overload again.
He needs calm under risk.
⸻
Night Alone
Later—
Zack stood alone.
Level 10.
Synergy capacity now six seconds.
He flexed his fingers.
Steel formed clean.
No flicker.
He felt stronger.
Not because of power.
Because of discipline.
He almost died last episode.
Now he's smarter.
⸻
Final Notification
As he turned to leave—
A subtle message appeared.
SYNERGY EVOLUTION PATH UNLOCKED
NEXT MILESTONE: 10-SECOND WINDOW
Zack stared at it.
Ten seconds.
That would change everything.
⸻
End of Episode 21.