So, let me get this straight.
I'm pretty sure the red things are pieces of the incomplete Philosopher's Stone, as we've seen the imperfect version of it about half a dozen times so far in the series. From the second image, we see the kid is eating (...) it. While I don't condone eating Rocks, this is very interesting as we can see the end result is, essentially, The Kid, but with a disturbing air of Envy-ness to him. Is he a Sin now, or what? Do you have to ingest the philosopher's stone to become one? You can't see it in the image, but he's standing over the crumpled body of Izumi (wah!). I got to thinking from this image, that maybe, because to do Human Transmutation, you need the stone, maaaaybe Envy tried to get the Kid to ingest the stone and then fuse the two of them together. The end result does look a little bit like a scary sort of Envy/Kid hybrid.
I know it's probably way too far fetched to even be a possibility, but I'd thought I'd throw it out there nevertheless. Maybe in tearing down this theory, other people can build up something more concrete?
Also, does anybody else think it would be cool if there were characters in this series who were symbolically linked to the Four Horsemen? Not that it would have anything to do with it at all, but I can't help but think Archer fits the bill for War perfectly, and Scar seems like Death--his self-proclaimed mission is the deliver the sinners, after all. I dunno, I thought it would have been neat.
Okay, yeah. That's... all I really had to say.
*Throws self to the wolves*