Some TMNT stuff was always meant for grownups.
She's an outgoing, but somewhat unorganized and irresponsible woman.
In the Mirage comics, Robyn is the older sister of April, who, moved to Los Angeles, where she lives in a house on the water. She has an ex-husband named Colin, who she had divorced, a young son named Trevor who she has custody of, and a cat named Coolbean.
Although the two sisters had no contact for a long time, their relationship was still very tight, even though April's sense of order is not entirely able to agree with Robyn's lifestyle.
After years of separation, Robyn finally broke the ice and invited April to her home in L.A. After several months of living with her, they received word that their father had passed away. After attending the funeral together, the two sisters went their separate ways again when April inherited a large sum of money, allowing her to return to New York and buy an apartment complex (TMNT Vol. 1, #49, 51 - 62).
It was not until much later, however, that Robyn should learn that April, Robyn's own sister was not technically human, but rather a lively drawing brought to life by a magic crystal, which once belonged to her father, and later her former lodger Kirby.
After the Utroms were publicly revealed on Earth, Robyn was attacked by an extra-terrestrial, cancerous disease from which she threatened to die from. The Turtles and the Utrom doctor Glurin put all means at their disposal in order to fight the ulcer, and together they managed to find a remedy that could prevent future diseases on Earth. On this occasion, Robyn learned of the Turtles, got to know them personally, and thanked them for rescuing her.
- Robyn was originally going to be named June.