Hidden Rafael is the evolution of Rafael and now a Matrix Bakugan. He evolved into this form when three of six fallen angels, Abigor, Wallow, and Gressil, and Matrix himself gave him new powers when Rafael was dying from a battle. He belongs to Valentin.
Felnas Destroyer: Play before you roll. Rafael can sacrifice 400 Gs to have the Gate Card switch with one of Valentin's Gate Cards, and another 500 Gs to make the opponent not be able to activate anything for four turns. This Ability cannot be prevented nor countered in any way no matter what.
Aerial Draco Lane: Rafael gains G-Power equal to half of the opponent Bakugan's base G-Power. The opponent can also not do anything for three turns. This Gate cannot be prevented nor countered in any way no matter what.
The beings who evolved Rafael into Hidden Rafael (Abigor, Wallow, and Gressil) are based of the fallen angels of the same names from the 2007 film Ghost Rider. (Unlike their namesakes, the three beings are part of a group of six beings.)
Also, these three beings, along with Matrix, gave Rafael his Matrix Attributes. (Abigor, being a demon of wind, upgraded Rafael's Ventus Attribute to its Matrix alter ego with the influence of Matrix. Wallow, being a demon of water, gave Rafael the Matrix Aquos Attribute, also thanks to the influence of Matrix. Gressil, a demon of earth, gave Rafael his Matrix Subterra Attribute, with the help of Matrix.)
Rafael has nearly all of the Ability Cards from his previous form. However, some of them have been upgraded a bit more and even have changed names, such as Sonar Wind Commitment, which was Wind Commitment before Rafael evolved.
Rafael's Ability Felnas Destroyer was named after the Kanohi Mask wore by Makuta Gorast from the LEGO franchise BIONICLE.
Ironically, Hidden Rafael's and Gorast's color scheme are quite similar to each other.