u/_herus_

Let's assume that they found out about Shadow before Eggman did. For example, Tails hacked into the GUN files. Then he with Sonic (or alone) comes to free Shadow. What would happen next?

(For lore reasons, pretend the giant machine in the middle isn't there.)

*Tails, aside from his mayoral duties, has spent the last day working in the lab on something that would help that version of Sonic he met recently. It wasn't the most difficult thing in the world, since, as it turned out, the Dark Gaia's power wasn't too different to work with to the Chaos Energy. Though, the dependency of the power on time of the day took a bit to figure out how to work around. On the other hand, the nervous system interface wasn't difficult to create, Tails has had some experience making those before.*

*Eventually, Tails completes his work and sits down in his chair, waiting for Sonic to arrive.*

Hahah... I still can't believe it...

...

*Tails looks around and realizes he's not where he's supposed to be and quickly calms down.*

...

Doesn't matter. It's all over anyway. They'll be able to handle me disappearing one more time.

*A Chaos Emerald seems to be causing it. Around it, is a visible protective field, and on the ground beside it, is unconscious Tails.*

(Just to be absolutely clear. This Emerald is Fake, and has absolutely no power whatsoever. Just a fancy looking piece of glass, if you will. The effect described in the title cannot be applied on the global scale, it does not ruin the arc.)

*Due to him working with Nega, Tails decided not to get involved in the conflict between the two sides. He watched it all, from the beginning, to when the wave of transformation spread through the Empire.*

This is an interesting power. I wonder if it's any similar to the one trick I know...

*He leans on the railing, and keeps looking at the center of the empire through his binoculars.*

*Tails appears in the OM dimension after going through the portal. A few seconds, nothing is happening, he just curiously studies his new surroundings. The darkened color scheme of the area feels almost calming.*

*But then, he **remembers**. All previously blocked parts of his memory are unlocked, even the ones he thought he'd erased from his mind forever. Thousands of years of memories being suddenly back, it's too much for the small fox to handle.*

Hah, hah... Of course. Of course...

None of them would understand what I'm trying to do. I have to strike first, before they even think of stopping me.

(This takes place right after Tails found the ring portal.)