There's an explanation, it wasn't posted when I first wrote about it.
It's basically a prototype Arcle that was made before Kuuga's.
The belt is incomplete because of lack of the Amadam that's present in Kuuga's.
The lack of Amadam causes the users to go berserk even easier.
The previous user went crazy and the belt was sealed inside the Coffin of Darkness.
The ruins where the Kuuga Arcle was sealed was labeled with Coffin of Light.
Mika's father was one of the scientists that found everything. His research included notes on the prototype Arcle.
Mika finds this 10 years after the end of the show, 3 years before the novel starts.
After sighting a few Gurongi, she goes to the ruins where the prototype Arcle is.
Her first form is white. The black form's eyes flashes between red and black, then completely black when she loses control to it. It's basically Kuuga with some minor differences, like smaller horns.
She fights an unnamed Gurongi in her white form, but it's killed by a different Gurongi before she can finish it off. Later she fights a jellyfish Gurongi, Rider Kicks it and is shocked by the explosion she caused.
She eventually faces a Go lion, she goes from white to black out of rage.
She uses steel frames and changes them into cannons, she shoots a huge beam out of Tokyo Tower. Godai shows up and stops her. The novel ends with the belt still in her.
There's also a new Beat Chaser 3000, Godai sticks Gouram on it while fighting Mika. The police have also developed new weapons to fight the Gurongi, Ichijo actually kills one. Ra-Baruba-De, the rose girl, escapes yet again. She's still alive at the end of the novel too lol
Nope, it's just text. You basically have to use your imagination for the novel exclusive Riders/forms. Apart from Cyclone, since he was featured in games and even has a Figuarts.
And, I'm picking up the Kuuga novel now
