Board Thread:Episode Discussion/@comment-4010415-20170717151617/@comment-26397825-20170718052756

Octavia' also had fire dust infused in the blade and looked like the fire slashes Adam has made in the past, which explains that. Fire blades leave a trail of fire where they swing, like what Octavia's did, but those slashes don't travel forward like Weiss's did. They're stuck to being there length of the blade away.