I'll add a little bit-
Oma Zi-O's Time Powers are POTENT, far FAR higher than baseline and layered.
Time Jackers are time manipulators and they are trying to hijack the timeline of Oma Zi-O for their own means.
For instance, the weakest Time Jacker (Heure and Oura) is able to do a full-universe Timestop. They can resist each other's Time Stops.
Their leader Swartz shrugs and is able to Time Stop Heure and Oura anyways.
Then Swartz rips out Heure and Oura's powers for himself, amplifying his Time Powers further, absorbs the power of a Multiverse Buster (Kamen Rider Decade), and ultimately his general potency is still under Tsukuyomi in terms of Time Manipulation, and above even her is Oma Zi-O.
So we have
Oma Zi-O > Tsukuyomi > Swartz (Another Decade) > Swartz (Normal) > Time Jackers (Heure, Oura) = Universal Scale Time Powers
Oma Zi-O also natively can tell when time is being tampered with and can teleport to the location of said tampering as he pleases, so you can't really pull surprise tactics on him.
Oma Zi-O also treats paradoxes as a joke and kind of toys with time trying to do anything to him. If something happens to him in the series, it's literally because he allows it.
The first time, he was in human form and simply allowed himself to get Time Paradox'd, then promptly came back as a lesson for his younger self.
The second time, the entire future where he became the King of Time stopped existing entirely. He shouldn't exist. He essentially went "Oh, looks like someone is tampering with time. Go take a look at that lackie." and continued stroking his metaphorical beard on his throne.
The third time, after he once again willingly let himself get paradox'd (By his younger self who got Oma Zi-O powers), he literally willed himself back into existing because some punk (Another Oma Zi-O, basically a monster copy of Oma Zi-O) tried to copy his powers and he took offense to it/the audience screaming his name was annoying and he basically told them to shut up.
Another thing are Ride Watches, the thing that holds Oma Zi-O's powers and whatnot. These are basically the very physical representation of whatever essence is inside's literal history. Press an empty one up against something and it's history will literally get drained into it. When a Kamen Rider gets their power drained by a Ride Watch, they literally never were that Kamen Rider ever.
They also aren't limited to Kamen Riders, since a Ride Watch of the Super Sentai Ryusoul Red exists.
That wouldn't be so potent, if it wasn't for the fact that the Ride Watch was able to override and fully assimilate Kamen Rider Gaim's history.
Mind you, Gaim is the person who scales above Kamen Rider Saver, who became one with an infinite Multiverse.
The Gaim novel had Gaim solo a Kamen Rider who became one with the Multiverse.
Sitting in the center of the lotus was the great heavenly demon who carried forth the world's end — the awakened false god of the lotus, Saver!
"…Kugai Kudou!"
"The Saver System has reached completion. The time for salvation has come."
"Salvation…you mean, creating a Golden Fruit and becoming a god?"
Kamen Rider Saver himself is an Artificial M.o.B so he is directly scalable to other M.o.Bs
The first, most immediate sensation was color.
He was being swallowed by every kind of color in existence.
After that was every other sensation. Sound. Scent. Touch. Visceral sensation — no, everything. Everything was engulfing him.
Everything, a mixture of everything, enveloping him into chaos and beating around him like a storm.
The same state, recurring eternally — and yet all still in a single moment.
The infinite colors eventually condensed into shapes. What had once been an explosion of color had now become a myriad of different scenes.
Taking all of it in, he understood what the flood of sensations was. He had come to understand everything.
Everything before his eyes — everything he could feel was "the world". Every space and every time was unfolding in front of him.
But there was no joy to be found there.
As he desperately tried to hold his sense of self together, he was swept away by the vast universe.
The infinite plane of worlds, each shining with its own history.
Countless stories of countless worlds, and with them — countless amounts of malice and hostility.
There was something wicked that treated mass slaughter as a game. There was something that resembled an angel of God. There were those who used monsters to kill each other.
Those who had evolved in a different way from Helheim. Those who were beyond death. Evil spirits who devoured humans. Extraterrestrial beings who imitated humans. Demons who wished to alter history. Those who resembled vampires.
And there were more. Those with the memories of the Earth. Incarnations of desire. Those who exploited the energy of the universe. Illusory demons born from despair. One hundred and eight artificial life forms —
Countless stories of countless worlds unfolded in front of him, all tied together by a thread of malice and hostility, made up of one common idea.
Countlessly-large Multiverse
Such a man should have overcome life and death itself.
He should have become a transcendent being free from physical bounds, integrated into the vast multiverse.
He had surpassed time, surpassed space — but because of that, such a man had no future.
With no future, he thus had no concept of creation.
Life evolves. Evolution is creation. Even with the cruelty of the cosmic system called Helheim, there was one thing that was certain.
No matter how much the man had overcome life and death, if he could not understand creation, it was no different from "death".
Thus, the man had not overcome life or death after all — he was simply just dead.
A meaningless shadow that merely happened to be projected onto the world — a ghost.
Such a man was fighting to erase the five living beings who denied his ideas.
In the midst of his battles, the man had perished many times. Each time, the cycle would repeat. And then, he would perish once again.
Transcended Time and Space and beame one with the Multiverse itself.
How long had they been fighting?
It felt as if they had always been fighting, and yet it felt as if they had only just started.
But still, they had fought. They fought. They fought to the very end.
Their enemy had revived after every single defeat, and they were hurt and exhausted.
But they refused to give up. Their hearts would not falter.
The world is not hell, because we know we'll never be alone.
We are not weak. We'll overcome any kind of pain we suffer.
So we'll stand up to protect. Not for our own sakes, but for the sake of the world.
We'll never let an empty ghost like you make the world into your toy!
And they defeated him many times over — tens, hundreds, thousands of times.
Their enemy had finally revealed his true form.
Bones poured out from the Cracks in droves, as if amassing into a vast collection of "death" itself.
Maja Arms…The heretical path of the serpent…!
The giant vacant skeleton that revealed the emptiness of Kugai Kudou's soul — Armored Rider Saver Maja Arms.
"Hmph…I guess we're really getting started now!"
Zack was laughing confidently, but there was still a tinge of apparent fatigue in his voice.
And beyond just Zack; Mitsuzane, Takatora, Oren, Jounouchi…all of them were at their limit.
But they could not afford to lose. If this was their limit, they simply had to exceed that limit.
That was how they had always fought, and that would always be how they fought.
We're not afraid to fight. We believe in the hope ahead of us…!
Maja Squash…!
Saver swung down his sword of calamity — the Graveyard Blade — and the myriad of bones became a rushing wave.
The five heroes gathered all of their strength to confront the wave and stood —
Countless stories of countless worlds.
When possibilities converged with other possibilities, occasionally, a new world would come forth.
It would be a fleeting one like an illusion — but it would still be a world.
And although this was a world of death envisioned by Kugai Kudou, it was also a gap between the worlds.
It was a place where possibilities converged with other possibilities.
Ryugen. Zangetsu. Bravo. Gridon. Knuckle.
There was one shared image between all five of their hearts.
— The hero.
Another confirmation of a Multiverse. An Amped Ryugen, Zangetsu, Bravo, Gridon, and Knuckle kills Saver tens of thousands of times and although mentally taxed and fatigued, Saver can never actually die.
There was one shared image between all five of their hearts.
— The hero.
If there was something that must be protected, they would rush in like a knight in a gale, even if it meant going to the end of the world.
The hope that the five of them — no, the hope that all of humanity envisioned — was the true gold that would crush the gilded lies.
The people's emotions drew in those possibilities, and incarnated them into a new story.
Now, the world shall play out this tale! The heroes of the grand finale — the Deus ex Machina!Banana Arms! Knight of Spear!
The aura of a giant banana, shining like a golden spear, blew away the mass of bones rushing towards them.
"Huh…?"
Zack looked around, but he could see nobody there. He couldn't even hear any voice.
But Zack had no doubt about it. He could feel "his" presence.
"Kaito…is that you?"Pinecone Arms! A single strike! In the shadow!
Then, a large flurry of black spears — Shadow Pines — flew towards Saver.
As the Shadow Pine spears pierced through Saver, he screamed in pain, like a roaring beast.
Oren and Jounouchi watched the spectacle in a daze.
"…What just happened?"
"Hassy…!"Maja Sparking!
Full to the brim with fury, Saver gathered a large mass of bones and formed them into a giant bone arm looming over their heads.
He swung the bone arm down with a thunderous roar.
"Gh…!"
Zangetsu had his Sonic Arrow and was about to fire, when —
Peach Energy Arms!
Cherry Energy Arms!
The bone arm was barraged with a rain of light arrows.
All of it was completely crushed and ground into dust.
— Nothing's changed after all, has it, Chief?
— Can't believe you had to get me to step in for you, though.
Somehow, Takatora felt as if he could hear those voices. And then —Lemon Energy Arms!
Fight power! Fight power!
Fight! Fight! Fight! Fight! F-F-F-F-Fight!
Saver had a giant hole in his chest.
A deadly Sonic Volley from a Sonic Arrow had pierced right through him.
"Ryooooooooumaaaaaaaaaaaaaa…!"
Saver let out a blood-curling shriek and fell to the ground.
And with that, Saver's deathly Zawame began to collapse.
Basically f*cking everyone who ever died is resurrected and amped by Kouta, they blast Saver to kingdom come which finally is enough to kill Saver.
Before anyone could process what exactly had just happened, everything around them began to collapse.
The earth split into pieces. The Bodhi tree had collapsed, and the lotus flower in the sky withered and scattered into petals.
"Hey, wait, what's happening to us now!?"
Zack was caught off guard by the sudden turn of events.
"Kugai Kudou's world…is collapsing."
Mitsuzane understood what that meant. If Kugai Kudou's world was collapsing, that meant Kugai Kudou himself had finally been destroyed.
The world (Could be planet or Universe, the Japanese word used can mean both) that Saver made to overwhelm the heroes breaks apart upon Saver's death.
And thus, only the warrior in silver and the bone monster were left behind in the collapsing world of death.
"…Kouta…Kazuraba."
Saver, who should have almost completely lost his sense of self, called out the name of the warrior facing him.
There was still a faint sense of will within his voice.
"…The Golden…Fruit…"
The skeletal dinosaur lumbered towards the warrior in silver, step by step.
"…I…will use that power…to save…humanity…"
"Hey. What was it you actually wanted to save?"
The silver warrior's question was not one that came from a transcendent being, but from a single mere human.
"I…wanted…I…wanted to…save humanity — "
"You melted into the world and disappeared, and what you actually wanted to save was…yourself, right?"
"…Save…me…"
Saver's last remaining sense of will completely disappeared.
What was left was nothing more than an empty monster, one that roared its death knell in a perishing world.
Even in his final throes, after reaching his apex, he still desperately reached out for Kouta's Forbidden Fruit.
tl;dr, Kamen Rider Saver 1) Integrated and fused with an Infinite Multiverse, able to rewrite and destroy anything to his whim 2) Because of infinite possibilities, for every time you kill him, he can infinitely respawn because another timeline spawned from the possibility where he didn't die, 3) The Riders that Kouta amped via Friendship powers was still wittling down Saver and later outright bypassed their infinite respawn
A ride watch just went "lol all of that is mine now".
Also being that they're both riders, Oma Zi-O has both Saver and Kouta's powers in the above quote. So at any time, Oma Zi-O could just fuse with the Infinite Multiverse and become omnipresent.
In terms of sheer stats, Oma Zi-O has Infinite Multiversal AP/DC and Durability, hilariously low-balled 23 Quadrillion times FTL speed, Acausal, even when allowing himself to get Paradox'd/His acausality gets bypassed he can literally just will himself back into existence.
And really, would anyone here resist having a Ride Watch pressed into them and having their history taken? A Ride Watch is potent enough to absorb powers that scales above an entity who became one with Infinite Timelines. That level of Time Potency is nuts.
