Green glow (Dark Souls)

Such a thing noticed. Sometimes, hitting an enemy (not sure what seeking, perhaps hitting) at the point of impact flashes green glow. Don't know whether it's the original game, we are talking about the Remastered. What is it? Thought maybe it was humanity, so it's murder or something? Or is it the weapon effect some work? Noticed two, seemingly nothing like swords. Great sword of the Abyss (corrupted version of the sword of the Arteries) and the sword of the Lord of Graves (claw Nito). Who will explain this? Beat the normal mobs in the city of the Undead.
UPD: I get it. Indicate contact after breaking through protect (shield for example). After that, there is an increased damage and is lit with green effect. Hmm. In the original version, too? I do not remember anything.

And additional question. The aforementioned sword of the Arteries is a blow. Powerful, one-handed version. There visual 2 stroke. In fact, how many have not tested - is the only one. This is the norm or a bug of some kind? (I suspect that didn't account for something during the transition to 60 fps when developing Remastered version)