original_query: What was the purpose of introducing the character "Sister" in the crossover and why was Teresa never mentioned by Eve, Michael, or Shannon McBain on One Life to Live?
query: What was the purpose of introducing the character Teresa in the One Life to Live/General Hospital crossover, and why was she never mentioned by other McBain family members on One Life to Live?
answer: Teresa was a new character created to facilitate the crossover.  The explanation given was that only John and Thomas McBain knew of her existence; Thomas was only shown as a ghost or in flashbacks on One Life to Live and did not mention her.