That's a stretch and a half, right there.
So far, IMU's powers have to do with either demonic possessions, or with the void/erasure, as per the kanji of his name.
It's related to darkness only as far as his design is bloated in ink (which could be a further link to "erasure"), and you could interpret the evilness of the yokai forms he bestows on the Gorosei as "darkness", but BB's fruit is a whole different type of dark, the scientific absence of light and pulling-in gravity of the black hole.