The time I was fused with my cat and sent into the Dragon Ball world

Merging Consequences

Seeing Future Zamasu rejecting fusion, Black just grins. "It doesn't matter if you reject this." He says, swapping his earring and forcing the fusion. Future Zamasu tries to stop it, but its too late. Black forcing his body into Primal Rosé as well for the fusion to be as strong as possible, he collides with Zamasu with a mad laugh as Future Zamasu screams in panic. A flash of light consumes the area, everyone but myself covering their eyes. I simply shut mine and wait. When I open them, my eyes focus on a fused Zamasu with long white hair, white fur, and immense energy on par with my own. This just the starting power, too, which concerns me. Moving quickly before he can talk, I clash against him and initiate physical combat, but he's actually equal with me as we trade blows. His style is changed, a blend of Black and Zamasu, but something is off. His attacks are weaker than his power indicates. Something internal is going on. Grabbing Zamasu, he fires a ki spear at me, only for me to flip while maintaining grip to redirect it, causing a ground explosion that I throw him at. Firing Kachin blocks to add on pressure, I release a huge wave of then into the destruction.

Future and Present Gato look at each other, having the same idea from my knowledge from training. Present Gato looks at Present Zamasu.
"I want to try something with my future self. We're separate people, so fusion could help here." He says, wanting to try and ensure the safety of both timelines. Present Zamasu takes a moment, then looks at his single potara.
"I don't know what I'l be able to do here with my one." He responds, visibly concerned.
"But I can do something." Another voice says, causing everyone to look over that isn't me or Fused Zamasu, as we're still throwing hands in the distance, explosions and destruction in abundance. Gowasu stands with a calm expression with Shin. The Supreme Kais of Universe 10 and 7 are now present in this battle. Gowasu was the one who spoke. "I understand you want to help, so I won't punish you. I will provide my own Potara Earrings to aid this situation."

Goku looks at Shin, then Vegeta. Vegeta scowls.
"I am not fusing with you, Kakarot!" He complains, very unhappy right now with this. Goku becomes serious.
"If we don't fuse, we'll all die." He responds, stern and serious. Vegeta takes a moment, then grunts.
"Fine. Supreme Kai, give me the earring." He responds reluctantly, unhappy about this. Shin nods, giving the earrings to Goku and Vegeta as Gowasu gives the future and present version of my son the earrings.

As my more stable balance begins to fade out and Divine Duality begins to fade, two blurs of speed get in the way of a punch from Zamasu. One is a dark blue, the other a bright white with sparks of lightning. Now, normally, one fusion wouldn't be enough, but Vegito is stronger than normal with Blue Evolution as well.

This new Merged Gato has Ultimate as well, making him extremely powerful. As I move back to recover, Vegito and Merged Gato strike together. The double punch that starts off the battle strikes physically and spiritually.

The cracks in reality, however... haven't closed. Eating a Senzu Bean, I regain my full strength and sense it. Multiple groups watching this battle. I turn to look at the cracks in reality. Using so much power caused this kind of damage. Returning to watching the battle, I begin to process how this has to end. I need to win this, but how? If I don't master Divine Duality, I won't have the power to keep up. My mind begins to think at speeds it shouldn't be able to, visualising. Upgrading the visualisation. Making it easier to handle. Focusing it. Making it so much more comprehensive.

I find myself in a familiar space. The place I met the others who used Ancestral Strength. I turn and look at the faces. The masses of people who used this power. They seem so much... clearer. I'm thinking too fast. I need to clear my mind. Closing my eyes, whispers around me fade out. Everything becomes quiet. Clearing my mind, I focus on the comprehensive visualisation.

"...No, too overcomplicated."

It becomes simpler.

"These powers are simple concepts. Destructive rage and instinctive movement. Balance them."

Silence.

"Reign it in, and master it."

Vegito due to using so much power, defuses. Merged Gato defends Goku and Vegeta, a brief spark of something beyond Ultimate showing in red sparks of lightning and red eyes. As Zamasu pulls his arm back, his body seizes up.

Soulscape.

Body stolen me and Zoom grab the Goku Black side of the fused soul, the other half of the soul helping. This conflicted fused Zamasu is experiencing an internal and external struggle. Resistance on two fronts. The soul pushes them both back, but the fused soul begins to absorb the conflicted half into itself, the me and Zoom that owned the body moving back. Future Zamasu pushes hard to stop the absorption, but he can't.
"Finish this. End the Zero Mortal Plan!" He shouts to the souls of my other self and Zoom before vanishing. Suddenly, the soul of Fused Zamasu, despite the conflict being gone, takes damage from a strike from the outside.

Outside.

A silver and purple glowing figure floats in front of Fused Zamasu. Zamasu floats back.
"How...?" He questions, terrified and angry. "How did you master the technique of the gods while I, the ultimate god, cannot?"

Silence.

No reaction.

Then, a voice comes from the figure.

"You couldn't ever reach this because of your intentions. Your mind is too overloaded with thoughts." The voice says, calm and collected. Mine, but more ethereal and deep. Its kind of terrifying. "I've reached this through experience and training. You'd never reach this." The light breaks off, shattering like glass.

Silver hair.

Silver cat ears.

Silver tail.

Silver eyes.

A destructive purple flame mixed in with the Ultra Instinct aura.

It's done. Finally, I've mastered this power.

Mastered Divine Duality has been unlocked.