Prue Halliwell's death

 "Prue Halliwell's death shattered the Enchanted Trio, leaving a void that nothing could fill. Piper's screams echoed with rebellion and hatred for fate itself, while Phoebe's tears stained the Book of Shadows with torment and guilt. They had lost not only their strongest sister, but the foundation of their family.

Picking up the pieces was a painful journey. It began not with magic, but with the arrival of Paige Matthews—an unexpected sister who was at first a cruel reminder of loss, but who gradually became a beacon of hope. Under Piper's reluctant guidance, who was forced to turn her grief into strength, and Phoebe's faith in a new beginning, they re-formed the Enchanted Trio. They could never replace Prue, but instead learned to fight to honor her memory. From the ashes of loss, they forged a new family, a new strength, proving that even broken, the Halliwell sisterhood is still the most powerful magic."