Knight of Cygnus: Soul Master

Because its common sense to get powerstrike? O.o
In first job you definitely need Powerstrike, HP Increase, and Slash Blast. 3 most mandatory skills.

And like ShiKage said, Soul Blade is a must. It's as important as a Bandit's SB and as important as an F/P's Fire Arrow. It's mandatory for early levels of 2nd job.

Fire arrow is not an adequate example in this circumstance, fire/poison mages can get through second job with no fire arrow at all. Closer example would be a sin and their lucky seven (albeit that isn't 100% accurate either, sins use lucky seven even longer).