This is Kamen Rider MetsubouJinrai. Looks like they'll use the base suit of Horobi so probably Horobi is the one who will transform into this. The suit might remind you of Kamen Rider Thouser, but this isn't even the repaint / retool of any of the suits. It's completely new and original!
When it comes MetsubouJinrai Driver Unit, it does use pretty much of a similar gimmicks as that of Zero-Two Driver Unit. The Driver Unit can be inserted on the left slot of Zero-One Driver and can be opened.
Here's the First scan of Kamen Rider Saikou.
Need to be harsh on this. His suit is completely black. Not even a single gold line on his suit. Even his eyes are black. A bit of poor design.