Who's the Adult Rafal near the end of the series?
I've seen and read people theories across the internet and comes to three conclusions:
1. Its Alternate timelines where Rafal was raised by a scholar instead of a priest.
Points suggesting it: In ch/ep 1, Rafal was raised by a priest. Yet Adult Rafal mentioned he was raised by a scholar. This could possibly suggest an alternate what if scenario. Implications also suggest that Adult Rafal timeline is the our real one.
Points against it: There's not much evidence to suggest the sudden timeline PoV shift. And also doesn't explain why Rafal letter to Potoski still exist in this timeline. Although the latter can still be explained as constant point in both timelines even if Rafal story itself changed.
2. Rafal survived the execution and made an escape.
Points suggesting it: We never seen Rafal corpse, we only see him tied up, and then the executor light up the torch, and next panel shows a burnt wood without any trace of corpse or even bones. I've read somewhere that Poppy seeds are good for helping people sleep and they aren't venomous at all. The discrepancy of his origin can be be summed as him lying to mask himself away from Novak.
Points against it: It was pretty much shown Novak was there overseeing the execution till the end, which makes the scenario where Rafal able to escape sounds absurd.
3. They are different people.
Points suggesting it: It explain the discrepancy in his origin, and ensure that Rafal did die back then and thus creating no plot hole.
Point against it: It feel too much coincidence that there's exist two Rafal with similar face and interest.
Counter point: Name being similar isn't too odd, but the appearance being the same could be just metaphor by the author. As both Rafal embody the reckless desire in pursuit of knowledge/truth, both embody the same ideal but on the opposite side of a coin.
Regardless which is it I salute the author for leaving one final mystery to close the series. Not only it worked to leave a long lasting discourse for the readers/watchers, but it also it stays true with series' spirit of reaching for the truth. The last page of the manga and also the last scene of the anime embody this perfectly.