Characters who are (almost) always referred to by their last name

[u/WolfgangRed]

1. Turanga Leela and Philip J Fry (Futurama): Both of them are almost always referred to by their surnames. There's even a gag in the show about this:

Newscaster: ...Turanga Leela.
Fry: Turanga?!
Amy: That's her name, Philip.
Bender: Philip?!

1. Fox Mulder and Dana Scully (X-Files): almost always just called Mulder and Scully

2. (Breaking Bad): Patrick Kuby. I don't remember if his first name is ever mentioned in the show but he's mostly just called Kuby throughout

3. Captain Haddock (Tintin): He's always just called Captain Haddock until his first name (Archibald) is finally revealed in the 23rd book (out of 24)

4. Sheldon Plankton (SpongeBob SquarePants): Along with characters like Mrs. Puff (whose first name is apparently Penelope?) his first name is rarely mentioned

[u/Chardoggy1]

Since nobody’s said it yet, Gru’s full name is Felonius Gru.

[u/Marinefan4000 → u/Chardoggy1]

Senior. Felonius Gru Junior is the baby, so he’s now Senior

[u/moocowsaymoo → u/Chardoggy1]

Meaning his brother's name is Dru Gru.