Krizalid (クリザリッド, Kurizariddo) acts as the mid and final boss of The King of Fighters '99.
He was designed to be a stylish and earnestly strong boss, though the supervising designer at the time admits, "I think I overdid it a little." A number of Krizalid's unused graphics were made available to the public in the Dreamcast release of the title. 
He was made to be the ultimate Kyo Kusanagi clone, outfitted with a special suit to feed data of fighters into his body during battle. This was achieved by cloning K' (rather than Kyo directly). As a side effect, he gained some of K's memories and believed Whip to be his sister. He was ordered to activate the thousands of Kyo clones around the world by using his suit. In order to gather the battle data necessary for the activation period, he fights the winning team of the King of Fighters tournament.
After his defeat, the Kyo clones were neutralized and his superior fatally crushed Krizalid by throwing a boulder at him. Heidern inquires if Krizalid remembers anything including his real name. He simply cannot remember and in the Ikari team ending, Whip reveals to Krizalid of his status as a clone, died shorty after out of treachery. According to the novels, his corpse was taken in by the Ikari mercenaries. Zero somehow later retrieved Krizalid's body and used the power of NESTS technology to bring him back to life. 
In KoF 2001, he resurfaces, revived by the Original Zero, and fights alongside him. K' faces Zero, Lin faces Ron, Maxima faces Glaugan and Krizalid faces Whip. Despite knowing the truth of his origin, he still calls Whip by her real name. Krizalid finally dies on his own merits, letting Whip's Voodoo entangle his foot and force him to lose balance, this allowed Whip to shoot him with her Desert Eagle resulting in his presumably second death. 
When Verse is subsequently defeated, Krizalid's soul emerges from it along with many others, and is suspected to be alive again as a result.
He is extremely powerful and he knows that, being very cocky and megalomaniacal at times, but he will serve NESTS loyally, no matter what. However, without his special suit his fighting abilities are still top-notch, and deep down he has a hard-working, earnest personality. He was incredibly loyal to Whip, with whom he shared a sibling-like bond.
- Pyrokinesis - Because of his blood, Krizalid can control fire.
- Create Fire - Krizalid can create fire from thin air.
- Fire Body - Krizalid can put his body on fire.
- Explosion - Krizalid can create an explosion around him or his opponent.
- Energy Projectile - Krizalid can fire a projectile of energy that hits his enemy twice.
- Energy Attacks - Krizalid can infuse his attacks with energy.
- Slashing Hands - Krizalid's hands can pierce and cut.
- Cutting Aura - Krizalid can create an aura of cutting energy around his hands.
- Cutting Wind - Krizalid can create an air current that can also cut anyone it touches.
- Multiple Attacks - Krizalid can attack several times at high speed.
Krizalid is an extremely powerful fighter sporting an inevitable anti-air move, high-gauge projectiles and dash attacks that are somewhat inescapable. Krizalid's Mid-Boss form isn't as powerful as his End-Boss self. Krizalid, like K', also has the ability to use flames, and some people consider Krizalid as the second clone of Kyo Kusanagi. Like most SNK Bosses, Krizalid is ridiculously strong, and inflicts above average damage, but suffers from having a poor quality AI if the player finds a "boring pattern" to take down Krizalid.
In his boss incarnations in the Arcade version, he cannot crouch like typical SNK bosses, but had standing attacks that must be guarded low. Legitimate crouching attack animations were created for him as the game was ported to the Dreamcast version. His playable version in 2002UM is based on the DC version of KOF99.
- Mechanical Bliss - The King of Fighters '99, first fight
- My Dear Fallen Angel - The King of Fighters '99, second fight
- Cutting Edge - The King of Fighters 2002 Unlimited Match
- Vs Krizalid - The King of Fighters 2
- Yoshiyuki Iwamoto - The King of Fighters '99, The King of Fighters 2000, The King of Fighters 2002 Unlimited Match
- Eiji Yano - The King of Fighters 2001, The King of Fighters 2002 Unlimited Match (Striker only)
- Masahito Kawanago - The King of Fighters World, The King of Fighters: All Star
- The King of Fighters '99 - Sub Boss and Final Boss
- The King of Fighters 2000 - as a PS2 Maniac Striker for K'
- The King of Fighters 2001 - as a Striker for Zero, unlockable as a Striker in PS2
- The King of Fighters 2002: Unlimited Match - final boss and assisting Zero; also in the winpose after defeat K'
- The King of Fighters 2 - battle character
- Days of Memories (fourth title) - unplayable
- The King of Fighters '98 Ultimate Match Online
- Kimi wa Hero
- The King of Fighters World
- The King of Fighters All Star
- The King of Fighters 2000 - in-game scenarios
- KOF: Maximum Impact 2 - background cameo
- The King of Fighters '94: Rebout - as a statue in Rugal's stage
- The King of Fighters: Battle de Paradise
- The King of Fighters 2002 - ending credits
- The King of Fighters XIV - As one of Verse's winquotes against K'.