The Unofficial RWBY Tabletop Game is a tabletop RPG created from the ground up by Andrew Diederich. Rather than using the d20 system popularized by Dungeons & Dragons, which is the most commonly used system for tabletop RPGs, Diederich built his own system from the ground up, which he refers to as the Rule of Cool, or RoC system. The RoC system is unique to almost all other tabletop game systems, as, rather than focusing primarily on dice rolls, the RoC system focuses primarily on the player coming up with unique, creative, and cool solutions to the problems they face while role playing. Of course, this opens the door to vastly varied styles of play, as the player can use truly unique combat strategies to try and impress their GM into giving them bonuses, rather than simply using variations of "I attack x enemy with y weapon", as is often the case with the d20 system. The RoC system was designed specifically with RWBY in mind, and as such accounts for such things as transforming Weapons, Dust, and Semblances. It is an incredibly simple game with nearly infinite possibilities, as long as you can find a role playable rationale, and it is an excellent starter tabletop for someone looking to get into the tabletop RPG scene, but scared off by the hundreds of pages of rules and regulations which accompany more mainstream tabletops, such as D&D.
The system is also extremely conducive to the Sir Bearingtons of the world, who want a wacky experience without actually breaking the game. Under this system, you can create your own original weapons, semblances, and even weapon modifications. One of my characters uses gauntlets and boots that are outfitted with buzzsaws which can be coated with Dust and ejected, then use his Polarity semblance to recall ejected saw blades. It can be as mundane or absurd as the GM allows, so long as it's balanced. As simple as the base system is, the degree to which it can be customized and homebrewed allows for some truly complex characters, weapons, and sessions.
Grab the free rulebook pdf here!
And check out Diederich's RWBY tabletop gaming reddit here!