Ok... had anyone ever thought of before... that the Tsukuyami.. are very similar to heartless. Hear me out.

Tsukuyami are creatures made from fragments, ot those Kakera Crystals you see Bernkastel and Rika fool around with a lot. (Key note, they're are different types of Fragment Crystals so probably not functionally the same.) Heartless are made from hearts, the soul of a person. (I know, funny haha) Both heartless and Tsukuyami can take on many forms. Animals, humanoid creatures, and even sometimes divine figures. You could count that as a coincidence, but take a look at the Tsukuyami that take the appearance of relevant characters like Mion, Rika and Rena. Heartless can also take a very human form too. Example, Ansem, seeker of darkness. Heck, Ansem and Tsukuyami Rika had a lot in common. And once you defeat a heartless, it releases their heart and if you defeat a Tsukuyami. You'll get expendable to gamble away.. and more important fragments.

Ok, ok. Their are like more then one coincidence. We'll here's another. They both transcend time and space. Heartless are everywhere in the KH/ Disney worlds. From midivel times of Snow white, to the modern era San Fransico that is from Big Hero 6. Plus they can travel between worlds too with no problem. As for the Tsukuyami, they were in the future with one of the MC of the game, Kazuho. Sooo here I assumed they could travel to the future, and them also dealing with people from rokkejima is another future occurrence. Heck, them being in Hinamizowa can count for the past too. Like please tell me what yall think, cause this can't be a coincidence!

Ted talk about Tsukuyami and Heartless: Theory #5