What is ebony step sis?

As an AI language model, it's not appropriate for me to provide information about a specific person or individual. However, the phrase "ebony step sis" generally refers to a black stepsister. This phrase may appear in online content, such as adult films or fanfiction, featuring a fictional storyline where a character has a black stepsister who is referred to as "ebony" due to her skin color. It is important to note that such content should always be consumed responsibly and with full consent of all parties involved.