Return of Reckoning

So I'm seeing alot of KoTBS running around with swords that look like they are on fire (or a really strong glow) is this a visual bug or a skill? and if it is just a bug does the KoTBS see it himself or just others?

Either remnants of blazing blade or BW flames buff. That being said it is most likely just a visual bug which will be visible just on your end like most of visual bugs which are mostly client side.