As expected in a parody, the characters for the series have similar personalities to their original counterparts; however some aspects are greatly exaggerated, as seen below.
In the abridged universe, Agent K is an agent working for MIB. He is bossy, strict and sometimes arrogant to people around him. Although he aids Agent J, his partner, he sometimes thinks J is a fail in life. He is rumoured to be in a relation with Agent L, which can be seen in Episode 1.
Agent J is an agent working for MIB and is mentored by his partner, Agent K. He is seen as an underdog by most of the agents, especially by K. His intelligence can vary at times, although he rarely makes an intelligent decision. This lead to many missions being compromised by him.
In Men In Black: The Abridged Series, Agent L is an agent working for MIB. Most of time she is seen as a slut and times she can be quite dumb too. She is in a relation with K. However, an incident in Episode 2 caused her to reveal some secret feelings for J.
He is the leader of MIB. He only made an appearance in Episode 1.
They were the first aliens J and K encountered together.
In Episode 1, they wanted to eat J because he killed one of their leaders which lived in sewers.
In the series, Galaktus was a fairly intelligent alien travelling galaxies for the soul purpose of murdering abridgers. Luckily, he was defeated by K in Episode 2. He was also a challenging fighter.
The Worm Aliens
In the abridged universe, The Worm Aliens are drug addicts. They work for the MIB.
He is an agent working for MIB who is a sex addict and made a brief appearance in Episode 1. Surprised, he likes to have sex with objects as well.
He was only mentioned by K in Episode 1 as a person who got raped by aliens ten times. It is hard to tell who Joe was in the episode because there were various agents walking by when K shouted out his name.
In the abridged universe, James Brixton is a fictionalised character based on the real James Bruxton. He appeared in Episode 2 as a young child who presumably loved Ponies and who became friends with an alien which was hunted by Galaktus. His role in the episode was quite important because J and K were trying to prevent that alien from having a bad influence on his abridging skills and to put a stop Galaktus's plans. Towards the end of the episode, we can only hear a more mature James Bruxton doing his first ever abridging series, and ironically failing at it.