Well this isn't unnatural at all!

Mist Flames

Tsuna did not know he had also unconsciously mimicked Mukuro's Mist Flames, unfortunately. He still remembers the first time with Lambos flames (and no, he was not blushing because of a bazooka...).

So you really can't say that it was his illusion that was floating just above the barrier of the three. Nope, not his. Not one bit his imitation. No. And in the corner of his eye, he can see Reborns twitching finger and his sigh.

"It wasn't me!" he cried out to his tutor as the audience looked at him in confusion and looked back at the illusion, which was a giant bag of marshmallows.

Reborn only arched an eyebrow and his fingers continued twitching. His beady black eyes held contemplation in them as his hand ever so slowly crept up to Leon.

"It wasn't me!" he repeated and clutched both his hands to his chest as he saw Leon transforming into a familiar green gun (if Tsuna knew that the barrier is supposedly indestructible he would be relieved but no, he still won't because its Reborn they're talking about).

"Tell me on egood reason to not give you to Verde, now." Reborn said with Leon pointed at the barrier.

Tsuna flailed and cover his head as he crouched down and then--

A giant Natsu was standing protectively in front of him.

Everyone's jaw dropped (Reborn and Kyoyas did not because they had an image to uphold and Mukuro because he was laughing his signature pineapple laugh). If one were to focus properly, they would have sensed the Mist Flames in them but they did not.

Byakuran however, is a different case. Said albino was looking up and staring at the back of marshmallows with stars in his eyes.

"Dont shoot!"

"I will shoot."

And then the infant shot. His shot pierced through the barrier and all of them wondered how but decided not to. Tsuna scrambled away from the bullet that barely missed him by a nick of his hair.

(How did he even manage to break the barrier when he wasn't even there!? Physically, of course. His Hyper Intuiton sobbed in disdain and Tsuna could faintly make out it saying to not ask. Tusna did not know his HI could talk!? [Somewhere along this madness, Giotto chuckled in his place in the ring.])

"Why'd you shoot!?" Tsuna cried to himself.

"Because I wanted to."

Tsuna sobbed to himself and at the same time, the giant bag of marshmallows was hugged by a love stricken Byakuran.

The rest stayed silent but stared in disbelief at the scene. Where was the epic fight they expected? The giant Natsu was still there though, said feline curled itself around Tsuna.

They also stared at the hitman in awe and fear. They could only think was how, and frankly, they also do not want to know at the same time.

====
A/N:

All of my endings may or may not be half assed... So.... Yeah...

And this is the part where I say I screwed with the original plot. I was actually planning to make it more 'fight here, fight there, FIGHT EVERYWHERE!' but eeeh... I had no motivation... 😂

Tsuna: I don't wanna die young... 😱

Me: ....you....aren't gonna die.... Probably...

Tsuna: WAS THAT HESITATION!?

Me: pssssh... No....?

Tsuna: THAT WAS A QUESTION!

Me: no it wasn't.

Reborn: you're not gonna die, yet.

Tsuna: WHAT'S WITH THE YET!?