Because you like Ford Prefect in The Hitchhiker's Guide to the Galaxy

Thanos is an intergalactic warlord, on the hunt for infinite power. See them in Marvel Cinematic Universe.

GLaDOS will supply the food when you get together: a delicious cake. Of course, it could just be a trap so she can kill you. It’s hard to say. See them in Portal Series.

Born and raised in the darkness, Bane is determined to have the city totally under his control so that he can demolish it. See them in DC Extended Universe.

Kesuke Miyagi is a karate expert who thinks the best way a scrawny high schooler can learn how to defend himself is by washing every surface in sight. See them in The Karate Kid.

Samwell Tarly is a scholar, not a fighter. But that's not good for an aspiring member of the Night's Watch. See them in Game of Thrones.

Deadpool thinks life is an endless series of train wrecks with only brief commercial-like breaks of happiness. See them in Deadpool.

Oliver Tate is extremely articulate but hopelessly awkward. That's not a recipe for teenage happiness. See them in Submarine.

An off-beat dork, John Egbert is funny, inventive, and endlessly optimistic. See them in Homestuck.

Sabriel is smart enough to understand the dangers that await her and brave enough to face them anyway. See them in Abhorsen Series.

Mabel Pines loves sparkles, animals, friendship, and fun. See them in Gravity Falls.

Marshall Eriksen is a lawyer in love who is enjoying life. See them in How I Met Your Mother.

Chewbacca is a loyal co-pilot who won't hesitate to rip your arm off. See them in Star Wars Series.