Whats its synergy; with the harp class? It makes sense,with the Bow/Harp. It seems like a rather 'fun' combo, in my eyes.
Are you asking what are the bonus skills?
Keep in mind I don't have this class (I tried bow and didn't like it) and I don't speak the language so I'm trying my best to understand what the translation means.
For harp, they are:
Aoe fire attack that repels enemies and inflicts a debuff
Aoe lightning attack that does a lot of damage.
Attack that goes in a straight line and hits enemies in the line.
For sword and shield, they are:
For 30 seconds, a forest guard (or 3? not sure) is summoned that attacks the enemy.
Some kind of attack, idk if it's aoe, that causes "massive fire damage"
Falling arrow skill that surrounds an enemy and puts them in a coma (might mean stun)