Board Thread:General Discussion/@comment-33053086-20171006004010/@comment-4010415-20171128030527

In Heroes and Monsters, you see everything red on him, including his sword's blade, glow red when he blocks the bullets that Blake shoots at him. That was him absorbing energy for his Semblance, when he later used on Yang.

Which, now that I think about it, is even sadder for Blake. She accidentally supplied him with the fuel he needed to cut off Yang's arm. Yikes.