As a battle between the fate of the omniverse is imminent the Counter force choses Benjamin Kirby Tennyson as humanitys master of the omniverse with both the servants and the omnitrix he will become the hero of heroes (goes through classic to omniverse)

In one world, two thirds of the Extella Trio are having a ball with who may be their greatest partners, Tamamo with an unlucky spiky teen with a mysterious right hand, Nero with a boy with more guts then one hundred spec ops soldiers, but what about the final member? Well she gets flung into a different world and entwines her fate with that of a young watch wearing hero of course!

"Severe genetic damage detected, should we attempt to repair?"

I loved this story so i decided to finish it this time. Sorry for the wait

After defeating Dagon and Vilgax, Plumbers sends Kevin to a mission. Meanwhile Max makes a deal with the mage association and sends Gwen and Ben to Fuyuki to investigate mysterious events. What they found was not what they expected.

A raging stormy night and dire consequences left Ben severely hurt and his Omnitrix destroyed. Leaving him trapped as Frankenstrike and with no clue where he is, or how to get home. Now his only solace is a mysterious human-like Transylian girl dressed in a white wedding gown. And the mysterious girl has mistakenly perceived him as someone she has desperately waited for.

one night Ben, and team tried to stop a mysterious shadowy figure from stealing the Alpha rune but everything suddenly went sideways. Ben was accidently sent through a portal and went missing for days. On the tenth day Ben reappeared ten years older, and wearing ancient roman armor and a amethyst butterfly ring, he has no memory or any idea where he disappeared to.

In this world Azmuth did not create the Omnitrix, but someone, a certain magician, created the Servantrix, an artifact that connects to the Throne of Heroes, allowing the user to transform into Servant / Heroic Spirits.

When Ben Tennyson visits Fuyuki on a trip for some Extra credits and some downtime, instead he finds himself locked into a bloody battle for a Wish-Granting Grail. With no other choice, Ben shall use the power of the Ultimatrix and newfound allies to put an end to the battle and uncover the truth of the Holy Grail War of Fuyuki.

The Mage's Association thought they had destroyed the Holy Grail, and thus Angra Mainyu. But they didn't realise that one mage would try to restart it by accident. And that accident got local hero Ben 10 involved in the War. As a Heroic Spirit. Now Ben isn't just fighting to save Bellwood from monsters. He's fighting to save himself. Waiting for me to rewrite it.

For centuries the Holy Grail War has operated in secret with no outside interferance, using the spirits of ancient heroes as Servants. Now a new definition of the word Hero enters the Grail War and will bring great change to everything. No Slash.