Often in Star Wars novels, there are antagonists. In the Yoda novel, it could be Sith or dark side users. They would be the main opponents of Yoda and his allies. Their presence would create conflict and drive the story forward. Yoda's interactions with them would show his strength and wisdom in combatting the dark side.
Grogu is a member of Yoda's species. He was raised at the Jedi Temple on Coruscant. But during the fall of the Republic, he was hidden away. His origin story is also tied to the events that led to the near - extinction of his species.
One key element is his time at the Jedi Temple. Another is the fall of the Republic which disrupted his life. Also, his species' rarity is an important part of his origin.
Grogu is a very cute and powerful character in Star Wars. He's a youngling of Yoda's species. Grogu was at the Jedi Temple during the fall but was rescued. He then had various adventures. He was found by Din Djarin, a Mandalorian bounty hunter. Grogu showed his Force abilities during their travels together, like using the Force to move objects and heal wounds at times. Eventually, his training as a Jedi was considered important by Luke Skywalker, who took him for a while to train him in the ways of the Jedi.