It depends. If you want to emphasize certain parts or make them stand out for a specific purpose, underlining can be helpful. But it's not a strict rule.
Well, typically, underlining in a short story isn't very common. Usually, bolding or italicizing is used for emphasis. But if it makes sense for your particular style or needs, you could underline.
I wouldn't say there's a definite yes or no. It might be okay to underline if it serves a clear purpose, like highlighting key points or creating a visual effect you want. However, in many cases, other formatting options might be more conventional.
Chapter 162, "Once and For All, Victory", is the clearest early answer because it turns Great Xia's situation into a concrete plot event. Early on, The remaining forty-plus Earth-digging Realm individuals continued to.... By the end, Before the cold beast tide arrived, Xia Hong had already successfully.... Inside the broader faction conflict storyline, the danger stops being abstract and the conflict around Great Xia becomes immediate, forcing the surrounding cast to react under pressure.
Chapter 82, "Whether I Can Do It or Not Is My Business", is the clearest early answer because it turns Luo Ming's situation into a concrete plot event. It opens with Leader, the number of people has been counted. and closes on I won't say much more." Xia Hong did not say much, and after two.... The key payoff is that the chapter closes with As Xia Hong finished speaking, the whole place fell silent., which gives Luo Ming a stronger narrative position and pushes the power growth onward.
Chapter 143, "Getting a Bargain and Being Malicious [Triple-Length Chapter]", is the clearest early answer because it turns Demon Sheep's situation into a concrete plot event. The chapter gives readers a real answer by opening on The group double-checked among themselves and quickly knew who it was. and ending on The mood among the Hunting Team became excited instantly..
Chapter 78, "Accepting the Grand Gift", 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 A unique valley with an excellent location, highly concealed and... and ending on Firstly, I'm afraid seeing it will remind me of people; secondly, I'm....
Chapter 164, "The World in the Mirror, Immortal", is the clearest early answer because it turns Yuwen Hu's situation into a concrete plot event. The chapter turns that into something concrete by moving from Below the bamboo building, the crowd was bustling, with faint noises... to He could tell from their tone that they were genuinely willing to do....
Chapter 107, "The Tremendous Peril of the North Slope Cliff【3-in-1 Mega Chapter】", is the clearest early answer because it turns Chen Ying's situation into a concrete plot event. It opens with If we still can't find them in Redwood Ridge tonight, we'll have to... and closes on Their stations are quite similar to the slope where Great Xia was....
Chapter 111, "Escape from Desperation [3-in-1 Mega Chapter]", is the clearest early answer because it turns Chen Ping's situation into a concrete plot event. Early on, After listening for a while, Chen Ying quietly descended, his waxy.... By the end, Chen Ying followed the sound and found a grown woman by the bonfire,....
Chapter 105, "New Home Construction, Strength Bottleneck [Two in One]", is the clearest early answer because it turns Mu Dong's situation into a concrete plot event. The chapter gives readers a real answer by opening on When the new house construction idea was first proposed, Mu Dong... and ending on And that's just for the four outer walls..
Chapter 117, "Teng Jiao Saliva and Poison Source [Combined Chapters]", is the clearest early answer because it turns Shi Ping's situation into a concrete plot event. It opens with Although Xia Hong understood this principle, he had no way to improve... and closes on Inside that meat, there was a pure white round pearl, emitting a....
Chapter 106, "Expanding Hunting Grounds, Camp Expansion [3-in-1]", is the clearest early answer because it turns Hunting Team's situation into a concrete plot event. The chapter turns that into something concrete by moving from Xia Hong made up his mind and quickly gathered Xia Chuan, Luo Yuan,... to Six months ago, with a Hunting Team composed of fifteen Logging....