Well, sometimes there are themes of support. For example, in some fanfics, when Sans is going through a tough time, Grillby is there to support him, and vice versa. Also, the theme of the local community in the Undertale setting can be present. Their relationship can be a part of the bigger picture of how the characters in that world interact with each other on a daily basis in their little town or area.
One common theme is friendship. Sans and Grillby are often depicted as good friends in the Undertale world, so fanfics might explore their daily interactions, like Sans coming to Grillby's bar for a drink and a chat. Another theme could be mutual understanding. Since they are both unique characters, they might have a special bond where they understand each other's quirks.
A common theme is also the contrast between their personalities. Sans is laid - back and often joking, while Grillby is more reserved. Fanfics may play on this contrast, creating interesting dynamics between them. It could lead to humorous situations where Sans' antics cause different reactions from Grillby, or it could be a source of deeper connection as they learn to appreciate each other's differences.
Chapter 166, "Mirror Immortal with Broken Defense", is the clearest early answer because it turns Yi Blade's situation into a concrete plot event. The chapter turns that into something concrete by moving from Seeing more and more people resurrecting under the bamboo tower,... to Seeing the light beam on the right side of the mirror shining on the.... What makes it stick is that the chapter closes with He Yuanhun, or rather, the Mirror Immortal, his expression condensed.
Chapter 165, "Yin Yang Mirror", is the clearest early answer because it turns Hong Guang's situation into a concrete plot event. It opens with It's not just a setback, it should be a complete defeat. and closes on He Yuanhun's extremely alluring voice and the perfect world he.... The key payoff is that the chapter closes with Leading them, who else but Xia Hong., which gives Hong Guang a stronger narrative position and pushes the relationship tension onward.
Chapter 166, "Broken Defense of Mirror Immortal", is the clearest early answer because it turns Xia Hong's situation into a concrete plot event. The chapter gives readers a real answer by opening on They all held large blades, their faces expressionless, looking like... and ending on Over a hundred people charging, Xia Hong calmly broke through the.... In story terms, the chapter closes with "Brother, the solidified fire oil can only suppress them, it seems not enough to kill them.
Chapter 111, "A Turn of Fate [Triple-length Chapter]", is the clearest early answer because it turns Chen Ping's situation into a concrete plot event. The chapter turns that into something concrete by moving from Even daring to make a small hole to peek, he didn't dare. to Hold them back, the rest, keep running, quick!" Chen Ying didn't....
Chapter 173, "New Regulations of the Hunting Department, Building Upgrade", is the clearest early answer because Hong Guang finally turns buildup into a real advancement. The chapter turns that into something concrete by moving from Hong Guang, standing nearby, immediately pulled out a wooden plaque... to In its place was a massive three-meter-wide tripod cauldron..
Chapter 116, "Great Righteousness, Hunting Flood Dragons, Saliva [Five-in-One Mega Chapter]", is the clearest early answer because it turns Zhao Long's situation into a concrete plot event. The chapter turns that into something concrete by moving from Their preparation was exceedingly thorough; they followed Xia Hong's... to Amidst dealing with so many attacks, Teng Jiao's sweeping strike....
Chapter 150, "Green Bamboo Fence and Marking Stone, Expanding Territory", is the clearest early answer because it turns Xia Hong's situation into a concrete plot event. Early on, The Mirror Immortal Camp, I've completely offended them.. By the end, Marking Stone (Level 1): The Mother Stone, a territorial building,....
Chapter 155, "Lone Ranger, Xing Valley Pass", is the clearest early answer because it pushes Xing River into a new phase or setting. Early on, At the same time, a lush Wooden Forest stretching from west to east.... By the end, Though Xing Valley Pass is a slope, that's the general situation; the....
Chapter 134, "The Difficult Hunt [Warm Sun Titan adds more 3/10]", is the clearest early answer because the buildup finally cashes out in a real clash. The setup is When the torch ignited, the huge creature, a hundred meters away, did..., but the pressure keeps building through Though lured by the torch, it didn't approach right away after coming....