Who is poetic sister?

There's no widely known figure or entity called "Poetic Sister." It's possible you're thinking of something else or that it's a term used in a specific context that I'm not familiar with.

Could you please provide more context or information about what you're looking for? For example:

* Where did you encounter this term? (A book, a website, a conversation)

* What is the general topic or subject matter? (Poetry, literature, something else)

With more information, I might be able to help you understand what "Poetic Sister" refers to.