So Black Desert Online patched in the Kunoichi and Ninja Class just a few days ago, myself and pretty sure many others were awaiting this class for a long time.
The class itself plays pretty much like a melee glass cannon. After quickly rush leveling this character to 50+(it's not that hard if you already have a main character progressed in the game, had 2 mates reach level 55 on the first day) I consider the difficulty curve of the character to be pretty high. The class itself is extremely agile, lots of movement, disappearing, positioning, launch attacks, and strange inputs to put together pretty deadly combos. While the inputs are strange at first it's probably something I just need to get used to and to learn different traits of attacks.
The Kunoichi and Ninja aren't identical, they have similarities in combat styles but they have a few certain skills that one has and the other doesn't. I haven't exactly played out the Ninja class but it's considered to be more offensive-based than the Kunoichi by player opinion.
I agree with said opinion, it probably is considering the Kunoichi has a Block skill that I don't really fully utilize whereas the Ninja doesn't have such a technique but has more invulnerability-frame evasion techniques. Their awakening weapon in the future is also different. The Kunoichi gets a giant ring blade/chakuram(think Tira from SoulCalibur), and the Ninja gets hidden swords. Multiple Swords.
Source: Black Desert Tome Calculator
Other differences include Footwork dash that Ninja has but Kunoichi doesn't. Another would be the 100% and 200% rage skills are different for each class. Kunoichi's ground thrust is pretty slow and long to perform whereas the Ninja has like an instant ground stab drop. They share certain abilities like Fatal Blow but with these few differences the class does play quite different between both even more so when Awakening Weapon styles come later on.
Source: Dulfy.net & Inven.co.kr
All of the abilities and skills point to enhancing attack speed and AP with both these classes, there are stuns/launches the class has compared to others and a singular grapple. The other classes are a mix of grapple&knockdown, grapple & stun, stun/knockback, or knockdown & stun. Some more than others but playing a character like this in a war is where the real test is. I never really gauge the game on 1v1 fights as it really doesn't depict anything. Much like how a Blader is nigh impossible to chase down.
But this is just a quick overview of the class since I haven't had too much experience with it yet, here's a gameplay footage of the Kunoichi class.