FIRST Corsair CAN NOT equip 2-hands sword!!! Barbarian, Doppelsoeldner CAN, so ALL skills that need 2H sword can not used on Corsair.
Hello, I prepared corsair too. Big problem with Jolly Roger is that they give 25% ATK if you/party kill 5 mobs in 1 sec FOR only next 4 seconds, so for boss fights is useless. http://toswiki.treeofsaviorgame.com/mechanic/party
my build:
Swordsman:
1)Pain Barrier - must be maxed, is extremly usefull on boss and pvp. No knock back, knock down or stiffness - with good evad. stat = MVP (example: NO Pain Barrier: https://youtu.be/zWMTPCyo8T8?t=2733
WITH Pain Barrier: https://youtu.be/zWMTPCyo8T8?t=19201)
2)Concentrate - max level for number of hits. Compared with Gung Ho - better to have hits that seconds on boss and PVP, because you must dodge, run, avoid attacks, etc and Concentrate have no time limit.
3)Restrain - max lelvel for 20% faint. For fast atack corsair 5 hits is less that 1s so will stun everybody.
- all other skills are useles at corsair. Thrust - level 1 to push away, you can push a cleric from Safety Zone and …
Barbarian:
1)Cleave, Seism(AOE=5!!!), Helm Chopper max - good dmg, big AOE.
2)Frenzy - max, corsair is all about crit and fast autoatack with 2 weapons.
3)Stomping Kick - level 1, for jump on heads 
Corsair:
1)Jolly Roger, 1 level 30 sec with 16 sec cooldown… usefull only on mob packs, most in party.
2)Iron Hook - Keel Hauling PVP only.
3) Dust Devil and Doepper - to have some skills to atack with good dmg.
4) Double Weapon Assault - there OP buff of corsair, now you can hit with both armed hands.
5) Unlock Chest - PVE only build…