A lance is unsheathed, a warning breathed,
The battle lines starkly drawn
Now slashes of red begin to spread.
The innocent suffers on.
What monstrous spawn has settled upon
This field of unblemished snow?
Think evening recall or drumbeats withal
Or lacework that's knotty also.
It's a plain old riddle this time. The answer is a single English word.
I really ought to mention that my plain old riddle involves multiple definitions of the same word and a cryptic-style clue. Sorry about that.