[On his part, Subaru has been rather confused by the shift in his not!bf's mood, but has chalked it up to him being annoyed at the world (and though it's not entirely wrong, it's not entirely right, either). Really, the only thing that matters to him is that he still continues to visit him, however short or tense those meetings might be.]
[He smells the blood almost immediately, as he is walking back from checking up on his brother. He has half the mind to simply ignore it, assuming it to be what Sei meant it for, a strange way to call Subaru to him, almost like a twisted echo of the spell that was cast on him during the time the world was changed. But... there is always the possibility that it isn't that, that he's been hurt (though he has to admit the possibility is a slim one-- Sei is far too skilled to let the monsters get the upper hand over him), and he has to be sure.
In the end, he can't help but turn around and go into the forest, following the trail of blood, though delayed somewhat by a few monsters that smelled the same trail. It doesn't take him long to ensure they will no longer be able to continue following the blood.]