- Parley from Gunnerkrigg Court is called by her last name, because everyone's too nice to call her George.
- Johnathan Gabriel from Penny Arcade usually goes by "Gabe."
- Most of the pilots in Angels2200 are referred to by their callsign or last name.
- Nicknames instead of first or last names are pretty common among enlisted troops of all services, especially to enforce a One Steve Limit if there's more than one soldier of the same last name and rank.
- Nolan from Regular Guy.
- The title character of It's Walky! goes by Walkerton. He doesn't actually LIKE his nickname Walky (At best he tolerates it, there are only a few characters he actually doesn't mind calling him that). Almost no one calls him "David".
- Bonus points because even his parents call him Walky.
- All of the government-employed characters in Doomsday, My Dear refer to each other by last name: Zahra, Bowden, Young, et cetera. A few characters refer to Khepry and Chet by their first names, but no one uses Cyril's.
- Bittersweet Candy Bowl has Alec McCain, who is only referred to by his first name by Sue.
- Jardren Stiggs from Prophecy of the Circle prefers being called by his last name, even by friends.
- 25th Baam from Tower of God calls his best friend, Koon Agero Agnis, simply Mr. Koon.
- Muneca Powell of Pacificators is such a Proper Lady, she even calls her best friend Kathy Lee by her last name. The only time Muneca doesn't refer to somebody by their last name is when speaking with children.
- In Supernatural Law by Batton Lash, Alanna Wolff and Jeff Byrd refer to each other by their surnames, though they are clearly both friends and business partners, if not each others' Love Interest.
- In The Order of the Stick, Vaarsuvius refers to people they respect by title and last name. They normally refer to people he/she doesn't respect (such as Belkar, Elan and Miko) by race or class ("the halfling," "the bard" and "the paladin," respectively). Nale is an exception, being referred to as "Nale" because he doesn't have a last name or a single class to pigeonhole him into.
- Despite Dr. Jekyll frequently being called by his first name, Henry, in The Search For Henry Jekyll, his alter-ego Hyde is almost never referred to by his given name, Edward.
- In Girl Genius, Gil and Tarvek are almost permanently on last-name terms with each other - jusitified in that there was a mutual betrayal when they were children that led to Tarvek getting sent back to his Big, Screwed-Up Family, then when they met as teenagers in Paris that didn't go so well either. At the moment, they're both rivals for Agatha's affections. They do sometimes refer to each other by first name when speaking to Agatha though, usually when expressing the fact that they don't hate each other as much as they pretend.
Last Name Basis / Web Comics
Examples of Last-Name Basis in Web Comics.