Another good option could be Whis. Whis is very knowledgeable and powerful. Pairing him with Caway would allow for some really cool storylines. He could train Caway in the ways of the angels, and Caway could bring a fresh and different energy to Whis's rather calm and collected world.
The length of DB mangas differs. It depends on factors like the story's complexity and the author's vision. Some might run for just a few volumes, while others could have dozens.
One interesting story could be about Caway's hidden powers. Maybe she discovers she has a unique ability that can change the course of a big battle in the Dragon Ball Super universe.
I'm not sure specifically what 'db new story' is about without more context. It could be a new story related to a database (db), perhaps a new narrative within a database - related project, like a new data - entry story or a new development in a database system's history.
In my view, 'fiction db' is probably a term used in a particular field or industry related to fiction. It could be a database used by authors, publishers, or researchers to organize and access data about fictional works. But again, we'd need more details to know for sure.