Akari pats Zenatori's shoulder and says,

"This guy isnt that strong, I got this."

Zenatori says,

"Let me help, I'm pretty strong. Yachi go get Mashaka, we'll hold this thing off." 

Yachi says with awe,

"Okay, Zenatori sir!" 

Then she runs off.

Zenatori thinks, 

The monster says,

"My names Mamoru, I'm a member of the Death Stratum. To be honest I can see you trying to do this self sacrifice thing, but you will not stand a chance against me. Stop trying to be a hero."

Zenatori thinks,

"None of this is making sense, who's father? Who's this guy? Why are they targeting me?"

Before Zenatori can recollate his thoughts, Akari runs at it. She punches it while chanting, 

"Delimited Strike!"

It thinks can only think.

Suddenly it flings into the wall with a crash.

Akari follows up with, 

Zenatori thinks,

"How has she already learned Isotonic Force manipulation?"

Ice begins forming from her hands, but then fades away.

Akari slightly frustrated says,

"It seems even a prodigy such as myself, still has work to do."

Zenatori says in shock

"How did you do that?"

"We develop a faint trace of Isotonic Energy at birth, and it fully develops by the time you hit puberty. Since girls naturally hit it earlier I was able to train my Isotonic Force manipulation and mastered it at around 16. Unfortunately, the same isn't for my Syenji itself. My Ice method released before it could even shoot."

Suddenly it raises from the sediment trembling struggling to utter a sentence. It can only utter,

"I-I-I won't let you win."

Mashaka finally arrives and says,

"Expel."

Suddenly a whish of air goes by and a hole appears in the monsters body. It finally collaspes. 

Mashaka looks at its dead corpse and goes,

"It seems to be around a B-Divsion."