They aren't showing up.

What character's have actually interacted with the real Soichi because Evolt has been possessing him since before the series started?

Probably nobody. Heck, even in the early eps where he just seemed like the jovial cafe owner that was all Evolt being a dude disguised as another dude.

Does anyone know if we'll ever see evolts s true form and not the blob that we've seen so far depending on how many episodes we have left

Evolto's 'real form' appears to be Kamen Rider Evol Black Hole Form...so we already have.

I still has feeling Evolt will be has monster form especially for final battle.

Extremely unlikely.

Drive, Ghost, and Ex-Aid had Repainted Riders for the final enemy - even if Ex-Aid reverted to the normal one for the final battle, and Drive fought a completely different character in the final battle there. Evol Black Hole painted Black-and-Gold like the Lost Bottles is far more likely to be the final enemy.

Build Movie Poster:

http://www.tokunation.com/attachment...1&d=1528684175

Build Movie Trailer:

https://www.youtube.com/watch?v=1rG-G1_OjjA

Kamen Rider Blood

http://www.tokunation.com/attachment...1&d=1528785383

That has got to be the sexiest suit made of recycled/repainted parts ever made. Honestly it's awesome!!!