This is for the newbies who happened as of recently to have picked up this show.
Likely, many of you may noticed or not a coincidence that Alexander shares with Allen Walker from
D.Gray-Man.
Spoiler:
Both characters bear a quasi-similar scar on the left side of their faces.
Allen's runs through his eye down the cheek.
Alexander's starts just below his eye, and his has cross-like pattern.
I think this is or not just a reference to the symbology that this series uses.