After making his main roster debut on the Raw brand that July, his winning streak was immediately broken, he lost the NXT Championship to Samoa Joe the following month, and his on-screen character was subsequently altered.

Kesar is of Central American,[7] Puerto Rican,[8][9] Italian, Greek, Scandinavian, Croatian, British and Irish descent.

His father, Ted Concepcion, was a Puerto-Rican amateur wrestler who later trained in jiujitsu and became friends with Ricco Rodriguez and Ricardo Perez.

[18] On April 20, 2018, Kross return to AAA, aligning with Juventud Guerrera and Teddy Hart to attack Dr. Wagner Jr. and Hernandez.

[28] At Bound for Glory on October 14, Kross and Moose were defeated by Edwards and Tommy Dreamer in an impromptu tag match.

[31] At Impact Wrestling: Uncaged, Kross lost a fatal four-way for the title that also featured Moose and Brian Cage.

[40] Kross made his debut for Major League Wrestling (MLW) at the Fightland event on February 1, 2020, where he defeated Tom Lawlor.

[41] Before signing with WWE, Kesar made a one-off appearance on the February 16, 2015, episode of Raw as Kevin Kross, where he teamed with Darren Young to face The Ascension (Konnor and Viktor) in a match that resulted in a no contest.

[45] On the May 6 episode of NXT, under the new ring name Karrion Kross, he made his debut by defeating Leon Ruff in a squash match.

[53] On June 14 at In Your House, Kross successfully retained the championship by defeating Pete Dunne, Kyle O'Reilly, Johnny Gargano, and Adam Cole in a fatal 5-way match.

[56] While he was NXT Champion, Kross made his main roster debut on the July 19 episode of Raw, where he was defeated by Jeff Hardy in a non-title match in less than two minutes, marking his first pinfall loss in WWE.

[57] According to Kross in an interview after his release, the match originally was supposed to last 10-minutes before being abruptly shortened to 90 seconds just after he made his entrance to the ring.

[58] After losing the NXT Championship, Kross was transferred to Raw on its August 23 episode, performing without Scarlett and debuting a new look where he wore a gladiator helmet and suspenders in his entrance; his new attire and character direction was further criticized, with many deeming these changes unnecessary and poorly thought out.

Going by the Killer Kross name, he won his return debut match at SuperFight against Budd Heavy by referee stoppage.

[75] After a four-month hiatus, Kross made his return on the December 8 Tribute to the Troops special episode of SmackDown, taking part in the United States Championship #1 Contender Tournament, where he lost in the first round to Bobby Lashley.

[77] On SmackDown: New Year's Revolution, Kross, accompanied by Scarlett, attacked Bobby Lashley and the Street Profits, alongside the Authors of Pain (AOP) and Paul Ellering, who officially made their return to WWE, confirming their alliance in the process.

[79] At Night 2 of WrestleMania XL, the stable lost against The Pride in a Philadelphia Street Fight ending their feud.

[83] The feud concluded on the August 19 episode of Raw when The Final Testament lost to The New Day and Odyssey Jones in a Six-Man Tag Team Match.

On February 7, 2025, The Final Testament disbanded after AOP and Paul Ellering were released from their WWE Contracts, leaving Kross and Scarlett the only members left.

[85][86] Kesar is married to fellow professional wrestler Elizabeth Chihaia, better known by her ring name Scarlett Bordeaux.