
Quick answer — Shiho Kawaragi voices Helga Lui in Fantastic Children, Flandre in Princess Resurrection, Makiko Gregory in Hen Zemi (TV) and 12 more characters.
Shiho Kawaragi voices Helga Lui (Fantastic Children), Flandre (Princess Resurrection), Makiko Gregory (Hen Zemi (TV)), Sekai Saionji (School Days (TV)), Maki (Black Lagoon: The Second Barrage), Doumae (Full Metal Panic! The Second Raid), Rika Tsuwabuki (Good Luck Girl!), Megu Kakizaki (Rozen Maiden: Dreaming) and 7 more.
Helga Lui is voiced in Japanese by Shiho Kawaragi.