@Sinbad: That... sounds
quite similar to
what the
Lifestream [
https://youtu.be/-ww6qeily7Q?list=PLj5bkieyugVZkfgyCwR6bMVtnN29We5Gd&t=11 and]
Mako do. I guess supernaturally hazardous gas and energies are popular tropes in fiction (then again pollution and its effect on nature is quite a concern all in all, so many works allude to them)
It must be considered that Sephiroth endured the effects of the Lifestream directly several times, once after nearly being killed and another after his very individuality was destroyed, and that the Planet is not a, as weird it is to say it, Planet Level being, but way above Sephiroth himself in the 4-B tier due to the Lifestream itself. Now, if as you say, the Nebula gas puts Evolto at 3-A/Low 2-C in his ultimate form (or even just his abilities), then he would overpower Sephiroth's resistances with little issue.
@Akreious: It's actually pretty tricky, I made the
same mistake initially. Reality Warping is not quite an ability per-se and more of a macro-category that works as a means to give access to other abilities. From what I get, Nebula Gas having reality warping nature allows Evolto to possess through Biological means. I could be wrong due to lack of context, but merging different universes seems to go towards Space-Time Manipulation.
Sephy will likely come across the Black Hole obsession (hearing it in Evolto's evil and awesome voice), but the memory scan can unravel other information. Stuff like backup plans and such will be uncovered, such as if Evolto has backup cells. However, this is simply an equivalent of Sephiroth having prior information, whether he can counter or not what Evolto does depends entirely on how his owns skills measure up. To be honest, Sephiroth can endure resists powerful Gravity wells without issue, but there's a world of difference between that and a Black Hole isn't it? To be fair, I am pretty ignorant about Black Holes in general >_>;
Eeeeeeh... it's not quite slow as much as a pretty bad case of "as fast as whatever the plot needs to build up the melodrama" so it's indeed pretty unreliable for combat in itself.
Another thing we should bring up as well, we've been focusing on Evolto's offensive and how Sephiroth would hold up. But it's also necessary to discuss how how Sephiroth's offenses and Evolto's defenses fare in the fight. Due to his high AP, it's easy to think Spehy only resorts to a brute force, but he has many varied, if straightforward abilities, he does resort to tricks like Illusions and manipulation of the
senses and perceptions of his enemies to create openings based on what
he finds in their memories, he also tries to immobilize and outright crush them with telekinesis right away. He also has several haxes to incapacitate opponents, and though Evolto thanks to his biology likely resists Sephiroth's paralysis and transmutation into frogs, there are still possibilities like Sephiroth's own mind manipulation abilities if Evolto ends up with Jenova Cells within him (which isn't that unlikely as contact with Negative Lifestream is all that's needed, Sephiroth starts by summoning it to the field and he himself is made mostly of it), Time Stop, Sleep that can leave open for Flare (which is Atomic and Radiation Manipulation), the Supernova, Petrification (argueably, need confirmation if Evolto has dealt with something like this or if Biological resistance protects from Petrification)
Also, if Evolto can survive as long as his Cells remain and he can simply possess a new host, wouldn't that give him Immortality Types 6 and 8 (Parasitic and Reliant)?