Anonimo Bolognese says be absolutely merciless
"The true virtue of this art consists in being intimidating, and in possessing such ferocity as to appear to be on fire, with fierceness and absolute mercilessness in your countenance. Every slightest motion you make must exude a craving for delivering cruel blows; when you approach the opponent with such fierceness, you will completely wipe out his self-possession.” “Move in such a way as to give him the impression that every gesture from you carries the potential for inflicting a crippling wound. Make your attacks so cruel and violent that even the slightest blow is enough to fill the opponent with dread. In this art, you need to act and have the countenance of the cruelest of lions or the angriest of bears. Actually it wouldn't be a bad thing if you could make yourself look like a great devil and act like you wanted to whisk away his soul.” Anonimo Bolognese , translation by Stephen Fratus