[Sunred]

Huh, so they decided to go that route where instead of the actual onyomi they write it as 十, the number 10 in Chinese characters and also resembles a cross but read it as cross. FYI the word cross in Japanese is jyujika 十字架, which translates to 10-shaped rack/stand. In other words within the Japanese context it is seen as a a rack/stand that is in the shape of the number 10 and probably harnesses the power of the 10 seikens Rekka, Nagare, Ikazuchi, Gekidou, Hayate, Suzune, Saikou, Kurayami, Noroshi, and Kaiji so it all fits well.