To greatly simplify things from the novel each of Pagma's Sword Dances use preparatory movements that visually embody some sort of concept to call supernatural power into the sword. In Kill's case the specific footwork/choreography results in a strike is essentially condensed killing intent manifested as a physical phenomenon.
Basically where an average priestess or whatever would be dancing to call for rain, this "blacksmith"(lol?) does a dance that calls down "imma frickin' kill you with this sword".
Now that's the pros/cons of a party..
Cons: they mock ur low levels..
Pros: they buff u up and made fighting easier..
At least Grid is lil bit awesome like Weed for the ending arc 😂😂