It doesn't accomplish much, but when Ruber attacks her home Kayley has the guts to grab a mook's mace and take a swing at Ruber with it.
Ruber's defeat was pretty awesome, if only visually. He's cornered Kayley and Garrett into circle of rocks, and prepares to strike at them. They dodge, and Ruber ends up stabbing a stone- not just any stone, The Stone. Ruber tries to pull The Sword out, but to no avail; only the rightborn king of England can pull the Sword from The Stone. The Stone's power disintegrates Ruber in a fantastic display. Then Arthur shows up, still wounded, and effortlessly pulls The Sword free.
After realizing that being in agreement makes them capable of flight and fire breath, Devon and Cornwall have this awesome exchange before absolutely roasting the Griffon.