An anime/anime-inspired show, created by the late Monty Oum (although it is still going).
Show is about a world overrun with soulless monsters called Grimm. People who are skilled enough train from childhood to become Huntsmen and Huntresses to combat the Grimm.
While at Secondary combat schools (college/university age), students are grouped into teams of four made up of the initials of the team members (e.g. RWBY is Ruby Rose, Weiss Schnee, Blake Belladonna, and Yang Xiao Long).
Each character is unique, with their own individual look, personality, and weapon (which 9/10 times is also a gun or another weapon).
Episodes vary in length between 5 minutes and 30 minutes. There are currently 4 volumes (volume 5 starts in October). Volume 1 has 16 episodes, Volumes 2, 3, and 4 have 12 each.
It's best to start watching from the Red trailer and go through the 4 trailers before starting the series.