People are speculating that
Big (Nana Oosaki's) Ren has died due to drug overdose. It's because
Reira is seen talking to herself, but she begins to cry because Ren's no
longer there behind her. Nana Oosaki has gone missing, possibly
and as a theory, because she tried to commit suicide (look back
to 71-73ish chapters to understand) and everyone's trying to find her.
That's why Hachi was so relieved to find photos of her. Ren also might of died due to Ai Yazawa's fondness of the Sex Pistols which connects to
Sid Vicious--to died because of drugs I believe. Reira is sleeping/possibly
having an affair with Takumi because Takumi does not want Trapnest
to break up. He still considers Reira a sister, but nevertheless
he fools around with her while he's married. That may be one reason.
If you look back a couple chapters it shows a flash forward ( to the future)
when grown up Shin comes to visit Nana Komatsu in Room 707.
Hachi finds an envelope with Nana's photos. Later, she is found in
her room with her head on Nobu's shoulder. I think Nobu asks her
why doesn't she leave Takumi..not sure.

U think Ren died?? But ur theory is really logical, especially with the comparison with Sex Pistols.
So that would mean that Takumi and Hachi named their child after Ren?? And then it would make sense that Nana ran away and disappeared!!!
NOO that would be soo sad!!!

Ren was Hachi and Takumi's child

little Ren would be the first child and Satsuki the second. At least not all love is lost between these two .

Takumi really gave in to his love for Reira and his sudden vulnerabilty after all this time surprised me until in chapter 74 Ren commented that he was ready to embrace his sister to keep the band together/protect his kingdom/castle whatever... makes me think why did he start the band in the first place? maybe it wasnt for Reira but rather her voice??...I do wish Yazawa sensei clarified once and for all that Takumi really liked Hachi since he said if Hachi leaves him, everywhere will be a battlefield. I know many dislike Takumi but Hachi's heart ache for the last 3 chappies made me feel, let the girl get the guy and let him be good to her. .....since our alternate hero, Nobu and Yuri are all over each other anyway o.O ........... off the cuff, dont u think little Ren resembles Shin?? rather than Takumi? I thought little Ren was Reira and Shin's child at first!! But Satsuki is like her mother, hands down!! rofl!

In the last page (20th) currently scantalated isn't that Ren with Hachiko? You just see his back...

I mean, if you read between
the lines Yazawa's kind of leaning
towards that direction that Little Ren
is Hachi's child. Because I think they mentioned
child custody somewhere and how Little Ren
wants to stay in London...but the family is split.
Ren with Takumi (presumably daddy) and Satsuki
with Hachi (mommy) so I don't know really.
Yazawa's full of surprises.

that during the flashbacks Hachi was desperately trying to patch up things between Ren and Nana and perhaps Nana O never did reconcile wth Ren before he died....and I think that was the thing that might have devastated her before she decided to get lost...........she might have castigated herself that she couldnt see the signs of Ren's retreat and his problem..and that she had stubbornly refused to face Ren as she usually does until he came back to her...and maybe he died before he could...

....i presume the flash back scenes are set at the last days before a major change or something...maybe there arent many mysteries left unsolved except perhaps why little Ren doesnt want to go back to Japan and perhaps Satsuki's birth...Takumi must have decided to dissolve Trapnest after Ren might have OD-ed...but these are all my speculations...I still dont know why Takumi decided to shift to London...isnt that a career suicide? ....I understand if he would rent London studios for Reira's singing but its not like Yazawa indicated that Trapnest had any market or audience in the UK or internationally...

I had played with the thought of Ren being dead in future but little Ren being Takumi's son was somewhat indicative (lol, what a fertile or rather virile cassanova Takumi is!! ) however little Ren being Hachi's and not Reira's son was a bit odd, then I got the part where Yazawa wanted to surprise us with the fact that the first born was indeed a boy and not a girl! lol, there goes the idea that Sa-chan was the first born! I am sure many took it for granted that the future glimpse of Satsuki made us think that Hachi was currently pregnant with this child...however, i still wont raise my hopes up that little Ren is really Hachi's child until a more strong confirmation! :D

Now that we know that Ren is Hachi's child, there is still the question of who the father is. When we were first shown Satsuki, everyone then assumed that Takumi was indeed the father because of her appearance. Now that it appears Ren is Hachi's first child, there now throws the small possibility of it being Nobu's child out again. Some have been suggesting that Satsuki and Ren are twins, and though there's a possibility, I don't think so, since the doctor would have likely told her that she was having twins.

Never considered the possibility that little Ren might be Nobu and Hachi's child but this might be true..considering that they never did a paternity test...twins might be still b a possibility!!