Hmm..

WOW! that would be very interesting!!! :DD

But he's not a human (●'◡'●)ﾉ

Well.. Ciel's dad died and the manga is supernatural.. so who knows ?

I agree with you. :)

I thought the same too, but then I remembered a chapter in which undertaker and vincent are together so wouldn't that mean they were friends or something (? I don't know anymore ╥﹏╥

Hm.. Can't remember if they were once together in a chapter.. I don't think so, maybe you mean where Ciel got kidnapped from this one angel ? And his past got seen.. But it can also be that Undertaker might be Ciel's father, brother or even uncle.. He's so suspicious. ^^

Diedrich knew both Vincent and Undertaker, in the same time, and Undertaker has stated that he has lived for more than half a century being a shinigami, so... Sadly, that's hardly possible u.u

But yeah, he could be an ancestor, that would explain why he is so close to the Phantomhive family (the grandma's locket and him being with Vincent as one of the "evil nobles") (≧∀≦)

what about here? http://www.mangago.zone/read-manga/kuroshitsuji/an/kuroshitsuji-chapter-32.html/6/ but yeah I don't discard the idea that undertaker could be part of the Phantomhive family

True

Ah.. Hmm.. For all I know he acted as an informant for the Phantomhive family ever since Ciel's dad was alive. And he deeply cares for Ciel that he even wants to kill Sebastian cuz' he believes that Sebastian is making Ciel miserable..

Yep. But he existed before, look up the Campania arc, he said there he hadn't been called "shinigami" since half a century ago. So he already was one back then. Truth is he seems to care for Ciel, in some way, and he clearly held Vincent dear. He may be an ancestor. Or at least related to the family since some time ago.

We can't say it for now, let's wait for the new chapters and see what's his true relationship with the Phantomhive.

This Shinigami also mentioned that Ciel was different from the previous head in the school arc and in the Circus arc I believe that the Shinigami stated that he told Ciel's dad to care for life more, or something along those lines.

Hmm, maybe.