Note: "17. These sisters as Black and White Impermanence, the Chinese deities in charge of escorting spirits to the underworld."
(a)
(i) three marks of existence https://en.wikipedia.org/wiki/Three_marks_of_existence
("In Buddhism, the three marks of existence are three characteristics (Pali: tilakkhaṇa; Sanskrit: trilakṣaṇa) of all existence and beings, namely impermanence ([Pali:] anicca) [無常], unsatisfactoriness or suffering (dukkha)[苦], and non-self (anattā) [無我/非我]"
(ii) three marks of existence 三相 (佛教) https://zh.wikipedia.org/wiki/%E4%B8%89%E7%9B%B8_(%E4%BD%9B%E6%95%99)
(teaching in 南傳 上座部佛教)