Its still a mystery for me, why did undertaker revived the real ciel and what does he mean...

Ikrrr
Maybe he has some unfinished things with Vincent??
ORRRR
THE GRANDMOTHER OF OUR CIEL!!!
Ever wonder why Undertaker has that locket with Ciel's grandmother's name written on it??
It's still a mystery for me too

It would be hilarious if it turns out that undertaker is ciel's grandfather HAHAHAHAHA

But didn't Ciel meet his grandfather right after he made his contract with sebastian??
But now you're saying it, how does one become a grim reaper??

"Grandpa" is a name that OCiel used to call Tanaka in his youth. Makes sense, since he took care of him the most. His parental grandfather is still a mystery, though his name is confirmed as Cedric (from his family tree)

And according to the German grim reapers, people who committed suicide in life become grim reapers as punishment. So all the grim reapers we know (Grell, William, Ronald, Undertaker) were once real people who took their own lives.

I found something interesting and I thought you might wanna read it https://www.deviantart.com/may-may-meow/art/Undertaker-is-Ciel-s-grandfather-just-saying-621045102

Wait that's Tanaka??? All this time I thought it was his grandfather

So the first half is solid information, totally fine. The second half is confirmed as incorrect for three reasons. First, we know now that the 2CT is real, and it was RCiel that was being fed the vial of liquid. Secondly, that isn't a picture of Undertaker and Vincent, but a cameo appearance of Eric Slingby and Alan Humphries, two shinigami characters from a Kuro musical called 'The Most Beautiful Death in the World'. Thirdly, Undertaker confirmed himself that it was impossible for one person to make another soul theirs, so Vincent cannot be brought back to life through RCiel. I think that's why he was crying over his body burnt to ashes; he was able to resurrect RCiel when his body recovered, but Vincent had no body to resurrect, and therefore couldn't be brought back.

There's a whole bunch more that this theory doesn't mention, which is why I think it's kind of old, but it's still very likely Undy is their grandfather. I'll elaborate on one reason that some people seem to glance over: the Midford family.

If Undertaker was Vincent's father, it also means he would be the father of Francis, the Phantomhive daughter, and grandfather to Edward and Lizzie. Shinigami are visible to everyone if they're in disguise (butler Grell and circus performer Will) or close to death (Ryan Stoker before he died), but cannot be seen otherwise. If anyone has forgotten, Lizzie was able to see Grell and Ronald on the ship, even though they weren't in disguise and she wasn't close to death. So if Ciel can see them because of his lineage, so can Lizzie and Edward, which connects them all to Undertaker.

I have more, if anyone's interested, but that's enough for one reply.

Omg I didn't know someone already thought that undertaker might be ciel's grandfather. I was making a funny guess.

Omyghad. I didn't know it was really possible hahaha I mean I didn't there was already a theory about undertaker being ciel's grandfather. Thank you for the info

Oh yeah, the Undertaker-Grandfather theory is one of my favorites. It was kind of overshadowed by the 2CT until it got confirmed, and now it's being overshadowed by "what's RCiel's motive?" and "WTF IS HIS NAME!?"

Ohhh that's why I had never heard of it

I am ore and more becoming convinced that he IS grandfather. The date of his birth and death was closed by a bubble. I think it's not a coincidence.

It is because he died early, that's why he would be young as a Ripper (just as UT).