It could cause a sense of bittersweetness. The humor might lighten the mood, but the dog's death still tugs at the heartstrings, creating a conflicting emotional experience.
As of the latest chapters I've read, Megumi is still alive in the manga. Usually, such major character deaths are significant plot points and would be well-publicized if they occurred.
The main plot might be about the dog's reaction to its master's death. It could show the dog's confusion, grief, and perhaps its attempts to understand why its beloved master is no longer there.
Typically, megumi fanfic often focuses on his personality traits. His stoicism and determination are often highlighted. For example, in many fanfics, his unwavering resolve in the face of danger is a central theme.
Well, Megumi's story in the manga was full of twists and turns. She had to overcome various obstacles, and there were also some unexpected developments in her relationships with other characters.