The picture above (if my phone actually wants to work) is what I had imagined Tsuna's Degli outfit to be. I... might have changed it ever so slightly, but at least now you guys have a visual! ...I did my best...

(Edit: 4/30/16) Now that I come back to edit this, I cringe at the drawing...

The last battle was to be the Sky Battle, everyone vs. everyone. All the guardians on each side were to participate, if they weren't dead, that is. The Cervello brought Lussuria in on a gurney, and carried in Lambo with his air supply.

"There is one additional rule to this round," the Cervello said. "If you choose to do so, you may bring in one person who isn't a guardian to fight with you."

Xanxus stated, "I don't need anyone."

"I'll bring in Degli," Takeo said.

"Accepted," The Cervello said.

Tsuna jumped down from where he was perched in a tree. This would be interesting.

"Wow, I'm surprised. With all the training you've been doing, I'd have thought that you'd be a lot more arrogant by now," Degli said, landing beside who was supposed to be his partner against the Varia. "Glad to know that YOU know you're weak."

"Do you ever shut up?" Takeo groaned.

"Now that you've said it, no. Besides, insulting you is too much fun," Degli grinned under the mask.

Takeo sighed. "You better at least fight well," he huffed. 

"As you wish, Master." Degli playfully bowed to Takeo, who in turn looked the slightest bit flustered. "So," Degli turned toward the Cervello, "any special rules or conditions for me?"

One Cervello nodded. "Yes, you will wear one of these wristbands, along with all the guardians." They began handing out said wristbands, each with a small screen and a key-hole shaped like the Vongola rings. Tsuna's, however, was a bit different. Instead of the key-hole being a regular guardian's ring shape, it was the shape of the sky ring. 

Tsuna noticed one other thing about the bands. While the Cervello explained why they needed the bands (observation of the fight), Tsuna chuckled to himself about how there was a tiny injection needle placed at the clip of the band, most likely filled with a poison of sorts to make the battle more interesting. The next thing he noticed was the Guardians walking to their previous respective battlefields. No group cheer was done for Takeo. 

A minute or two later, everyone had arrived at the battlefields, and the Sky battle was about to begin. The Cervello went over the rules one last time. "We've set poles at each of the battlefields. At the top of each pole is a ring of the respective guardian."

"OI! Don't tell me we're fighting for them again!" Gokudera yelled in anger. 

Bel laughed. "In other words, we'll be fighting too?"

"You are all free to do so," the Cervello answered. "That is, if you are able to." 

It was then that the needle in the wristband injected whatever there was to be injected. Almost everyone collapsed, with the exception of Degli and Hibari, who only staggered a bit. 

"I see..." Degli said. 

"Everyone with a wristband was just administered a poison. This poison is called the Death Hitter. Once administered, it will paralyze the victim's nerves instantly. Even standing will prove to be difficult. Then, a burning pain will spread throughout the body, increasing gradually, until thirty minutes later, the victim will die. In this battle, the lives of all the guardians or allies are entrusted in the hands of the boss. That is the Sky Battle," the Cervello explained. 

"How do we reverse it?" Takeo asked, surprisingly calm.

"There is only one way to stop the progress of the poison. That is to insert the matching ring into each guardian's wristband. In Degli-san's case, the Sky ring. Once the ring is inserted in the indentation, it will activate the mechanism to administer the antidote stored in the wristband."

"So," Reborn said, "this battle is not only for the Sky ring. The guardian's rings have also become a crucial element."

"Exactly. Therefore, the condition for victory in the Sky battle is simply this. You must acquire all of the Vongola rings." The Cervello took out a chain and handed one to each candidate. "Use this chain to collect the full set of to Vongola rings." 

Degli grew impatient. The effects of the poison had slowly subsided for him (a result of training antibodies against many kinds of poisons. His immune system became very strong. It was amazing what all you could order off the internet without your parents knowing), but he knew the guardians wouldn't have the same luck. "C'mon, any way we could hurry this up and start?"

"Very well," The Cervello consented. "One last thing."

Degli groaned. 

"Once the battle has started, any outside interference from non-participating personnel is forbidden. That includes any special bullets," The Cervello said. 

"Understood." Reborn nodded. 

CRASH.

It seemed that Xanxus couldn't wait any longer. He had thrown a punch at an unsuspecting Takeo, who then flew backwards, and into the nearest wall (which was about twenty to twenty-five feet away, give or take).

"Let's hurry and get started. Isn't that what he said?" Xanxus grinned as he asked. 

Takeo stepped out of the rubble of the crumbling wall/building behind him. He was in dying will mode (Reborn had shot him), and had the utmost of confidence plastered on his face, even if he never did get any sort of weapon, or training in any sort of good fighting styles. Degli supposed that was why he was there. To save Takeo's ass. 

"If you wish to observe the fight, please come this way. Hurry please! The observation box is at the back of the school building. Like the guardian battles, please do not step out of the boundary of the infra-red sensors. Now, the Sky ring--Xanxus vs. Sawada Takeo--battle start!"

No more words were exchanged. The battle began. At the moment, Degli was watching the fighting in front of him. He planned to get his strength back before truly joining in. He was almost fully recovered from the poison. But for now... 

He would watch Xanxus beat the crap out of his brother.  

Tsuna sighed. In his current state, Takeo really had no chance against Xanxus. He was taking hit after hit after hit, not to mention a lot of damage. It seemed that he wouldn't be giving up any time soon, though. 

Degli realized he had better stop wasting his time watching a pointless battle, and start using it wisely to save his friends. 'Cloud first,' he decided. 

Arriving at the cloud tower, he found Hibari struggling to keep standing (even if he wouldn't admit it). Knocking the pole over, he found the ring and gave it to the Cloud guardian, who used it for his wristband. Degli could see a hint of relief and gratitude on the ravenette's face.

"Omnivore," he said, acknowledging the fact that Degli had basically just saved his life. 

Degli tipped his hat in return. 

Both heard a crash somewhere near the gym. "Favor," Degli said. "You go save the Storm, while I get the Rain."

The prefect nodded once and ran toward the Storm's arena, where Gokudera lay in wait. He wasn't able to get there. He was stopped by Takeo's body crashing into the school. Even though slightly annoyed (possibly pissed), he walked over to check if the boy was at least still breathing, but what he found was a pile of rubble and a rejuvenated Varia Storm guardian. 

So, naturally, fight. 

.....

Tsuna's time was very simple. He easily got to the Rain arena, and easily got the Rain ring, which he easily fit into the wristband. Did we mention it was easy? 

Degli sighed, and focused at the matter at hand. "Yamamoto, I need you to help Hibari with reviving the others. Can you do that?"

"Of course, Tsuna," he answered. 

"Thank you." 

.....

Takeo was not doing well. He was being beat to hell, and Xanxus wouldn't stop. 

'Of course he won't stop,' Takeo berated himself, 'he's freaking insane!'

With another punch, Takeo crashed to the ground. Funny, he could've sworn he heard a crack or two. Stupid, weak bones. 

"Oi, Xanxus. Done beating on him? Why don't you entertain me, instead?" the masked man requested. The contours of his mask lifted up at the cheeks, revealing that he was smiling underneath. 

Takeo thanked him in his head while his dying will disappeared and he slipped into unconsciousness. 

.....

Gokudera was in battle. After Hibari had gotten the ring for him, he went to the Lightning arena. What he found was a certain Varia member. Awake. With the Lightning ring he needed to save Lambo. 

"You!" Leviathan called. "You're the storm bomber boy! Get out of my way or I'm going to kill you."

"Hmph. There's not a thunder cloud in sight, how are you going to kill me? You're not that scary without that electric umbrella technique, are you?" Gokudera asked. 

"Fufu~ I see. You are mistaken, fool."

Gokudera was unfazed.

"If my technique could only be used on rainy days," Levi yelled, "you think I'd be a core member of the Varia!!? MY LEVI VOLTA IS AN ALL-WEATHER TECHNIQUE!" His umbrellas were now in the air, opened and ready.

Gokudera smirked. "That's what I thought. I've been waiting for this... the moment when all of your electric umbrellas are opened!" He stressed the word 'opened', releasing eight rocket bombs targeting each umbrella at the same time. 

The bombs hit their mark, and the umbrellas were no more. 

"My parabolas!" Levi sounded like he was whining. 

"I don't have time to play with you. Eat this!" Gokudera yelled. Dozens more rocket bombs were aimed for Levi. Sure enough, they hit their mark again. Levi wasn't dead (though with that destructive power, he should be), and Gokudera got the ring. Basically a win-win.

Gokudera carried the ring over to the sleeping Lambo, still on oxygen, and needing to get back to the hospital. His breathing was irregular as well; you could tell something was wrong. Gokudera inserted the ring. 

Lambo's breathing normalized after a minute. 

'I need to hurry and rescue the others, too!'

.....

Hibari, of all people, was having a hard time. He had managed to get the ring away from the maniacal prince long enough to cure Gokudera, but now had to face the 'genius' in serious battle. 

Bel laughed. "I think I'm going to enjoy this." 

Knives flew from his hand in arcs all around him, almost like they were floating.

Hibari rushed forward, looking for an open area to attack. Bel reacted by sending knives flying at Hibari, most of which he knocked down with his tonfas, but one was able to make it past his face. He paid no mind, as it didn't touch him at all, and kept running to circle around the prince. Next thing he knew, he had a fairly deep gash in his cheek, but he didn't know why. 

Bel smirked, continuing to throw knives all around the prefect. Hibari moved, and three more cuts appeared on his upper right arm. He was knocked down, multiple scrapes and cuts manifesting themselves on his arms and legs (though very few on his legs). Bel moved in for another attack, throwing knives directly at the seemingly subdued prefect. 

But the Prefect was not subdued. He was quick to move and catch the knives, inches away from the target, his face. It was then that he figured out that the knives were attached to strings, so...

He got serious. 

.....

The observation box was loud. Well, it wasn't so much the box itself as it was the people inside. One Dr. Shamal, Ken, Chikusa, Basil, and Reborn, all accounted for and amazed. 

Dr. Shamal and Basil were in their own little world, watching each battle intently, pointing out the very awesome things that were happening. 

Ken and Chikusa were worrying over Chrome. That's all they really cared about.

Reborn was watching the affairs of his pupil.  They weren't great. His student was passed out on the ground, in his boxers, and a murderous man just waiting to kill him (even if everything about that sentence is funny, it's still probably a bad thing). The only reason he was still alive was because of the man called Degli. Almost all the guardians were cured, but Takeo was down and neither party has the full Sky ring. 

It was all up to Degli now...