Mackenzie Dern

Mackenzie Lynne Dern was born on March 24, 1993, in Phoenix, Arizona, and grew up between the United States and Brazil inside one of jiu-jitsu's best-known families. Her father and coach, Wellington "Megaton" Dias, is a Gracie Humaita coral belt under Royler Gracie, and her stepmother Luciana Tavares is also a black belt. Dern began training around age three, competed throughout childhood, and by 14 was already entering adult divisions. BJJ Heroes credits her development to Megaton, Royler Gracie, and Leticia Ribeiro, with a lineage that runs through Royler to Megaton.

As a colored belt, Dern became one of the sport's most visible teenage prospects. She won IBJJF World titles at blue, purple, and brown belt, added Pan and European titles, and earned her black belt from Megaton in December 2012, three months before her 20th birthday. Her first major black-belt statement came quickly: in January 2013 she beat Luiza Monteiro at Copa Podio, then won the 2013 IBJJF European Open featherweight division. That early run established her as a featherweight who could threaten larger opponents from open guard rather than simply manage close matches.

Dern's competitive peak on the jiu-jitsu circuit came from 2014 through 2016. She won the 2014 IBJJF No-Gi Worlds featherweight title, the 2015 IBJJF World Championship featherweight title with a final win over Michelle Nicolini, the 2015 ADCC World Championship at -60 kg with wins over Kethe Engen, Beatriz Mesquita, and Nicolini, and 2015 World Pro titles at 55 kg and absolute. In that Abu Dhabi absolute run she defeated Gabi Garcia despite a major size difference, one of the signature upsets of modern women's BJJ. She followed with major 2016 results at the IBJJF Europeans, Pans, Worlds, World Pro, Asian Open, and Brazilian Nationals, finishing the period as the IBJJF's No. 1 ranked female black belt.

Technically, Dern was known for aggressive guard pulling, flexible open guard, and a submission game heavy on toe holds, kneebars, armbars, omoplatas, and back attacks. FloGrappling's archived match data and BJJ Heroes both show a high submission share across her professional grappling record, especially by toe hold. After years focused on MMA, she returned to grappling headlines in 2024 when FloGrappling reported her ADCC -55 kg invitation; she later withdrew from ADCC and faced Ffion Davies in a Craig Jones Invitational superfight, losing by armbar.

Dern moved into professional MMA in 2016 after already becoming a BJJ world champion. She fought for Legacy FC/LFA and Invicta before making her UFC debut in 2018, and her grappling remained the center of her MMA identity: the UFC lists eight submission wins, including rear naked chokes, armbars, and a kneebar over Hannah Cifers that made her the first woman to win a UFC fight by leg lock. By 2026 UFC records listed her as the women's strawweight champion after a 2025 decision win over Virna Jandiroba, while her official profile continued to describe her base as Brazilian jiu-jitsu and her favorite grappling techniques as leg locks and toe holds.