Confused... Please help clarify.... Nanae's Manga

Okay... So I'm a wee bit confused on some of the stuff that I've
read on the internet... Please take note I have NOT read the manga
nor have finished the Anime...

So for sure I know that there are two manga releases by Nanae-san...
One is the "Shinsengumi Imon Peacemaker" and the other
is "Peacemaker Kurogane". Tying the anime to the manga, I would
think the anime started with Shinsengumi Imon Peacemaker? Since I've
never seen the ending, did it just end with the first manga series
or the second? OR did the anime start with the second manga series,
Peacemaker Kurogane?

*Possible Spoiler*

The scanlations most of us have... The three volume one, is that
Peacemaker Kurogane or Shinsengumi Imon Peacemaker? I was talking to
an acquaintance back in Singapore and she kept going on and on, on
how unhappy she was that Okita is slowly but surely getting sick. To
those who have read both manga series, does the second one mention
this at all?

I'm not a fan of manga (have not even read past volume 3 of RK) so
please can someone tell me since, I haven't read this at all. Thank
you!