Usually just Oui, or Oui and Toto-sama.

I call her Hokusai and besides isn't Hokusai her family name?

Perverted Painter or just Hokusai, this is how a friend introduced me to the character when I was new the game so I call her that most of the time.

ST arts Saber Welfare

Wait the saber hoku or foreigner?

Usually call her hokusai, also theres another painter i call depressed painter

Hokusai( I know, it's not her name, but i don't care)

usually, I just call them Katsushika, independent on the ascension they're set on. cuz, you know, no matter if its Hokusai or Oui, they're both Katsushika.

Porn painter.

Hahahaha porn painter