Upon seeing Tsunade and Orochimaru, Sarutobi, already geared up in his battle armor and holding transformed Enma, narrowed his eyes, and gravely spoke towards Orochimaru. "So you have agreed, Orochimaru. I didn't expect you to have a shred of honor left but here you are."
"Honor... No, sensei. That's something a ninja doesn't need. I agreed because this is simply the most efficient way to accomplish my goals." Orochimaru gleefully rebuked, enjoying how angry his words made Sarutobi.
"If that's the case, why attack Konoha!? Why cause so much death and suffering in your home village!?" Sarutobi cried out, balling his fists in anger.
He still had a hard time believing his student actually did this. Didn't he do a good job as a teacher to instill the love for Konoha in Orochimaru? Defected or not... Sarutobi never thought Orochimaru would ever attack Konoha directly. Not like this.
Orochimaru, clearly enjoying Hiruzen's anger, just shrugged, "It seemed fun."
That made Sarutobi grit his teeth and turn to Tsunade as he hissed out, "Let's start the fight."
Tsunade, a bit bored of the drama between them, just shrugged. "If you are done talking." She beckoned them towards the central part of the roof that was surrounded by seals, leaving only a big area inside of them.
Sarutobi confidently moved inside while Orochimaru gave an apprehensive and cautious glance at the seals. The only comforting thing was that Sarutobi was not bothered by them so... Tsunade would not place a kill switch into the seals with Sarutobi still inside of them just to kill him, would she?
Orochimaru was uneasy but he believed she was too sentimental and soft for that. No matter how disrespectful she seemed, Orochimaru thought she still valued Sarutobi as her teacher.
When they both got inside, Tsunade kneeled down on the edge of the sealing circle and put her palm onto a marked area. The seals instantly flared into life, glowing red before a barrier rose into the air, creating a massive restricted area where nobody could get in or out. Not unless they got through Tsunade first.
The entire barrier was made by the example of the Four Violet Flames Formation that made a similar barrier but needed four people to power it up and keep it standing. Unlike that one, this barrier Jutsu needed only one anchor and power bank, which was Tsunade, and despite her being that, she could still move around and fight, as long as she didn't leave the range of the chakra transmission between the seals on her palm and the sealing barrier.
There would be no ANBU getting in to help Sarutobi nor would there be any unforeseen get-away chance for Orochimaru. Rei went so far to ascertain that, he even added an anti-space feature so not even reverse summoning would work.
Both Orochimaru and Sarutobi couldn't help but admire the barrier that sprang up around them. They were ninjas and adept at sealing for long enough time to recognize the danger of the barrier and partially unveil its functions with just a glance.
They both instantly recognized its origin was from the Uzumaki Sealing Arts. The same as the Chakra Barrier around Konoha and the Four Violet Flames Formation.
And while Orochimaru wondered when Konoha got stuff like this and how to steal it, Sarutobi wondered when Tsunade got stuff like this and how to... er, politically privatize it for his clan.
Only when their eyes coincidentally met did they realize they were here to fight to the death, and not admire a new Jutsu. That's how big Ninjutsu nerds they both were.
The atmosphere turned awkward for a second before both Sarutobi and Orochimaru wordlessly sprang forward at the same time, both trying to take advantage of the awkwardness of the other.
Enma in his staff form met Kusanagi blade, sending sparks all around as Orochimaru and Sarutobi entered the contest of strength. Despite his age, Sarutobi still had an edge though.
"You were again slacking in training your body, old boy." He teasingly pointed out while trying to put more of his weight into his weapon, "All those chemicals can not be good for your health. You gotta be more youthful."
Orochimaru inwardly cringed at that reference, imagining himself in green spandex and with a bowl haircut.
Of course, Sarutobi instantly capitalized on that slight distraction and his leg shot up... only narrowly missing Orochimaru's crotch because he noticed it at the last moment and managed to shift his body to the left.
"That was cheap!" Orochimaru exclaimed as he let Sarutobi win the weapon clash all the while he leaned to the left with his entire body, letting Sarutobi's staff harmlessly pass him as his Kusanagi sword slashed downward, aiming to get a good chunk out of Sarutobi's leg.
To Orochimaru's surprise, he managed to land a hit and cut off Sarutobi's leg right under his knee...
Only for Sarutobi to burst out of existence with a puff of smoke.
Orochimaru's eyes widened as he felt heat abruptly rising from behind him. He didn't have enough time to look at it. Sarutobi was too expert of a caster for that. Orochimaru quickly spun on his heel, his hands blurring in hand signs mid-spin, and when he was finally facing the source of the heat and realized it was not just a fireball but actually a boiling sea of mud...
He released the Water Wall Jutsu he was preparing to counter a fireball only for the water to be instantly suppressed by the far heavier mud while also being partly vaporized with a hiss due to the heat.
Sarutobi watched as Orochimaru was engulfed by his boiling mud but he didn't drop his guard. Orochimaru was a far too tricky opponent to do that.
This time, it wasn't needed as Orochimaru did not intend to attack. He simply rose from the ground on the opposite side of the arena from Sarutobi and started talking while cleaning the dust from his shoulders, "That was a good one. You almost got me. Using a shadow clone for distraction. I don't think I have ever seen you do that, sensei. And here I thought an old dog could not be taught new tricks."
Sarutobi didn't expect to defeat Orochimaru with that move but seeing him completely unharmed even though he managed to catch him off-guard was a bit disheartening. Contrary to his feelings, his tone was grandfatherly and light, "I was learning new tricks from Naruto, you see."
Orochimaru felt his ego sting a bit when he heard he was almost hit by tactics made by that orange-clad fool. It definitely showed on his face as Sarutobi chuckled at him, causing him to blank out his expression.
Mirth shining in his eyes, Sarutobi decided to verbally unbalance his opponent even more. "But you are starting to monologue. Does that mean the warm-up round is done and you are finally prepared to unleash your trump card?"
Orochimaru almost stumbled and Sarutobi smirked.
The brat was a hundred years too early to try winning a trash talk match against him. He probably already forgot who taught him all his psychological tricks.