It is revealed that Matrona survived the events from years ago. She intervenes to save Diane after she is cornered by the Commandments.
The bond between Diane and Matrona is a central theme, shifting from their previous strictly militaristic giant-warrior relationship to one of mutual protection. NanatsuNoTaizai2_Ep_18_ITA.mp4
This episode covers material roughly from Chapters 161 to 164 of the original manga. It is revealed that Matrona survived the events