Who is Waverly from The Princess Bride and what is their importance?

Waverly is Buttercup and Westley's daughter. Waverly is born on One Tree Island where the four companions seek refuge from Prince Humperdinck. Buttercup goes into distress during labor, and Fezzik shows amazing skill by performing an emergency cesarean section on Buttercup to save her and the baby. From the moment of Waverly's birth she has a special bond with Fezzik.