The biological father of Toshimasu is considered to be either Masuuji TAKIGAWA, a member of the clan led by Kazumasu TAKIGAWA who was the main vassal of Nobunaga ODA, or Masushige TAKIGAWA, and it is said that he was adopted because his biological mother re-married to Toshihisa.
利益の実父は織田信長の重臣滝川一益の一族（従兄弟あるいは甥）である滝川益氏（たきがわますうじ）か滝川益重（たきがわますしげ）とされ、実母が利久に再婚したためその養子になったのだとも言われる。