
Quick answer — Ai Satou voices Bertha in Darker than Black, Arima no Haha in His and Her Circumstances, Saranda in Black Jack and 8 more characters.
Ai Satou voices Bertha (Darker than Black), Arima no Haha (His and Her Circumstances), Saranda (Black Jack), Masako Aoi (Senpai is an Otokonoko), Gakuenchou (Gakuen Utopia Manabi Straight!), Harver Gongjag Bu-in (Doctor Elise: The Royal Lady with the Lamp), Chisato Kodate (Fafner), Tomo (Pokémon: Zoroark—Master of Illusions) and 3 more.
Bertha is voiced in Japanese by Ai Satou.