Not much of Grillby's personality has been shown. However, due to being made of fire, he seems terrified of water. This is shown in Undertale if Frisk interacts with him. Here, a message will pop up that says "Grillbz said that he'd offer you a glass of water, but he doesn't touch the stuff."
Grillby is shown to be competitive, since he works tirelessly all day in order to keep his diner as the most popular in town. Grillby seems to not like Muffet, this is mentioned in My Sunshine, Sans mentioned that him and Muffet always fight for customers, further supporting their rivalry.
Grillby is a fire monster that has glasses. He wears a black long sleeve uniform that has a white collar, a small grey bow-tie, and a few black buttons. During My Sunshine, he was seen wearing white gloves. However, in Love Part 1, when he was getting ready to fight some of Bete's pink creatures, he did not wear them.
Grillby makes a cameo in this episode. He is seen serving a burger to someone in front of his restaurant, vying desperately, and relentlessly, for customers. He soon looks angrily at Muffet upon realizing she is doing the same to get customers.
Grillby makes an even briefer cameo in this animation. He is seen getting ready to fight one of Bete's pink creatures in front of his restaurant, but him actually fighting it is not shown.
- In Yet Darker, Sans goes to Grillby's for a brief period of time. However, Grillby himself did not make an appearance in this episode. This is why "Yet Darker" is not listed in "History."
- Grillby currently doesn't have a voice actor.
|Villains||HATE ♡ Chara ♡ Bête Noire/Akumu ♡ Agate Lightvale ♡|
|Main Characters||Frisk ♡ Gaster ♡ Sans ♡ Flowey ♡/Asriel ♡ Undyne ♡ Papyrus ♡ Toriel ♡ Asgore ♡ Alphys ♡ Mettaton ♡|
|Side Characters||Jessica ♡ Amber Lightvale ♡ Cam ♡ Lily ♡ Robin ♡ Abigail ♡ Seth ♡ Zachary ♡ Hugo ♡ Ronan Cass ♡ Rave Rutrow ♡|
|Background Characters||Temmie ♡ Burgerpants ♡ Jerry ♡ Grillby ♡ Muffet ♡ Amalgamates ♡ Alina ♡|
|The Seven Wizards||Copper Lightvale ♡ Agate Lightvale ♡ Roy Goldburn ♡ Shane Goldburn ♡ Mila Rutrow ♡ Kody Fallenfire ♡ Rin Winterway ♡|