Rafaela (ラファエラ, Rafaera) was Claymore #2 during Luciela's time and Claymore #5 in Clare's Time.

Rafaela was seen first as Irene's pursuer.

Her power is considered equal to that of her elder sister, former Number 1; Luciela.

Rafaela was a part of the Organization's first experiment using a soul link to control an Awakened Being. The experiment fails causing her elder sister, Luciela, to lose control and fully awaken. Rafaela lost an eye, which she intentionally did not regenerate. She's blamed for the experiment backfiring, because of her 'weak heart'. Consequentially, she was stripped of her number and stayed inactive as a Claymore.

She appears to have been one of the longest lived Claymore so far (disregarding awakened warriors), as she was around from before Luciela's time when she met Teresa, who was still a young warrior in training.

Source: Wikipedia