Ky Kiske is a playable character in all games since the original Guilty Gear.
Akin to his rival Sol, Ky is a fundamental jack-of-all-trades character with intuitive normals with some acting as good pokes and/or decent anti-airs. He comes with a standard projectile (in the form of Stun Edge), a rising invulnerable-anti-air (Vapor Thrust), and expansion gap-closers (Stun Dipper, Needle Spike, Greed Sever, and his signature Overdrive, Ride the Lightning). The aforementioned Stun Dipper is an advancing low that can setup knockdowns, Greed Sever is a slow-yet-rewarding overhead, while his iconic Stun Edge Charge Attack (a mainstay product leftover from the original GG1's Charge mechanic) is a useful pressure-zoning tool. Overall, Ky is an average zoner and blockstring-pressure fighter rolled into one. Unlike Sol however, Ky is less on raw damage output and more on safe frame data, as he seemingly has to work more harder for his overall damage while losing out to pure specialists, yet is still well-rounded and easy to apply projectile lockdowns with.
In X, his moveset becomes far more refined with the removal of Needle Spike and the inclusion of the rather gimmicky Crescent Slash. However, as of XX, Crescent Slash is removed and replaced with the recurring Greed Sever as a practical overhead, as well as giving him his iconic setdown projectile mote in the form of his jumping and his new projectile Overdrive, Sacred Edge. XX Slash on the other hand, revamps his Stun Edge Charge Attack input, but also at the cost of rocketing him into the higher tiers with his Stun Edge frame advantage 50/50s on block (due to the increased travel speed and animation). In later games, he has been toned down since then.
In Λ Core, it in this game he gains far more extra tools. Lightning Javelin as a followup to Vapor Thrust works as an amazing finisher via the wallbounce it produces (which can be RC'd for further combo potential), his Force Break Lightning Sphere provides much frame advantage on block and can also lead into the Charge Drive followup for further damage on hit, with his Lightning Strike being able to provide the option to further forego his wakeup offense or not for extra damage. Likewise, his jumping also receives a Force Break variation in the form of Stun Rays, where Ky can plant a longer lasting projectile mote for further purposes. Despite being a beginner-friendly character, Ky has a fairly big number of FRC's, one for each his projectile attacks which make him adept at lockdown zoning.
In Plus R, he also gains the Force Break version of Greed Sever as a punishing fully-low-invulnerable overhead that serves as a great converter, as well as a new version Lightning Javelin for a faraway knockdown or for a wallstick near the corner instead.
Xrd -SIGN- however, massively reworks him in that while his base moveset is the same with his Force Breaks and other Λ Core additions removed, he gains a new gimmick known as Grinder Creation, where when connecting with any of his -based moves and his new Split Ciel, he leaves behind a "Grinder" that appears as a ring on the field where Ky last left it. Firing a projectile at it (Stun Edge, Stun Edge Charge Attack or Sacred Edge) enhances it through the use of Durandal Call, which increases the size, length and amount of hits (and by proxy frame advantage on block) depending on the projectile used. Durandal Call-based projectiles are elongated in the shape of a sword-shaped projectile extension. Due to the appearance of the DC-based projectile taking a while to emerge, Ky can effectively multi-task with delayed-disjointed zoning, allowing him to effectively oppress careless foes with well-placed Grinders+Durandal Call activations while still maintaining his old gameplan.
In STRIVE however, Durandal Call is then replaced with a new mechanic called Shock State, where Ky can effectively inflict increased untech-time with his lightning-based moves for extra extensions on his combos. His brand new Foudre Arc and Dire Eclat moves serve as a testament to this, with the former move being his new overhead that replaces Greed Sever and compliments Stun Dipper's low-hitting nature as a tandem mixup tool. His Stun Edge and Stun Edge Charge Attack inputs have also been reverted back to their pre-Slash commands.
In EX Mode via the XX games, Ky becomes a bit of a mirror to some of Sol's base moveset, while re-adding old moves such as the aforementioned Needle Spike and Crescent Slash. Likewise, his new Elegant ni Kiru (Elegantly Beheading) is his version of Sol's command throw, and his Grand Vapor Thrust also mirrors the Grand Viper in a similar vein. Both Grand Vapor Thrust and his Kiriharai (Cutting Sweep), the latter being Ky's prior version of Sol's Tataki Otoshi/Knockdown, reuse motions from the first version of Robo-Ky (the Impala Hunt and Aces High respectively). Also in Λ Core, Lightning Strike in EX Mode in converted into a Force Break.