You mean like this video posted on reddit:
Here ist the post with an explanation:
I guess so, I just haven't tested things to refine it.
You don't even need blade weapons with Olwen.
If your Olwen is +SPD, giving her Darting Blow + Hone Cavalry buff results in an additional 12 speed. With 44 speed during the player phase, there are very few things that aren't either dying. Same result as the blade tome but I guess you don't need to sacrifice a unit for it.