The movie is using characters from the first and second Borderlands games. Lilith and Roland are player characters and Dr. Tannis is an NPC in Borderlands 1. Kreig is a DLC character in BL2. Tiny Tina is an NPC in BL2 and 3, and a recent game called Tiny Tina's Wonderlands. There is a race of super beings called Sirens. They have different powers such as teleportation and gravity manipulation. There can only be seven Sirens in the universe at one time so they dont overpower everything. This is only a fraction of the lore of Borderlands. If you have the games, especially BL2, go ahead and start playing them. They are a lot of fun.

Borderlands is totally chaotic, irreverent humour, great action, and guns guns guns! The main character throughout all the series is the robot, Claptrap voiced by Jack Black. Corny humour, bad jokes, even worse gags, all game fans love to hate him lol. Nice reaction, hope you end up watching the movie!