ABOUT US
OUR MISSION
At ONYX Lacrosse, we are committed to developing leaders, resilient competitors, and dedicated teammates. Our program emphasizes strong foundational skills, exceptional lacrosse development, and the ability to compete with integrity while honoring the traditions of our great game. With more than 20 years of diverse club and playing experience in this area, the ONYX management team is built on knowledge, passion, and a deep understanding of athlete development.
REBEKAH IMMITT
Co-Founder/Director
Beka Immitt brings over 20 years of coaching and leadership experience to the club lacrosse community. A former Division I player and team captain, she also served as a Division I Assistant Coach and spent 10 years coaching youth lacrosse, along with eight years as a board member for Renegades Lacrosse. She is the Owner of Babies to Backpacks, a Developmental and Special Education Consultation service.
Beka is recognized for her strong communication, purposeful leadership, and commitment to athlete development. She emphasizes foundational skills, resilience, and accountability, preparing young women to compete with confidence and apply lessons from the field to life beyond the game. She lives in Denville, NJ with her husband and two children.
LEE SOUTHREN
CEO/Co-Founder
Lee is the Founder/CEO of both Riot lacrosse club (Boys) & NJ Turf Academy (Randolph). Lee brings over 20 years of club sports experience to the ONYX. A resident of Denville, NJ, Lee is married and has 4 sons. JP & Jake were standout lacrosse players at Randolph HS (2014/2016 grads), went on the play D1 (Quinnipiac) & D3 (Stevens). Twin sons Cole & Luke are currently Juniors at Gill St. Bernard's HS and play Lacrosse & Ice Hockey for the Knights
TIERNI FURLONG
Defense | Morris Knolls HS | Georgian Court University (D2, CACC)
Tierni is from Denville, New Jersey, where she built her foundation at Morris Knolls High School as a defender on the lacrosse field and earning All-Conference Honorable Mention recognition and being recognized as the 2021 National Girls and Women in Sports awardee. Known for her toughness, communication, and ability to anchor the back line, she set the defensive tone and became someone her teammates could always rely on in high-pressure moments.
She continued her career at the Division II level at Georgian Court University, where she elevated her impact both on and off the field. As a team captain, she led with accountability, composure, and consistency, earning the trust of her teammates and coaches playing in two CACC tournaments. In her collegiate career, she was in the National Honors Society, finished with a 4.0 GPA. Is a reflection of her leadership, excellence, and commitment to being more than just an athlete.
MACKENZI FURLONG
Attack | Morris Knolls HS | Mount St. Mary’s University (D1, MAAC)
Mackenzi Furlong is a Denville, NJ native and former Division I attacker at Mount St. Mary’s University. A two-time team captain, she earned First Team All-Conference honors, MAAC All-Academic recognition, and helped lead the Mount to a MAAC Regular Season Championship in 2024–2025. She finished her collegiate career with over 100 career points.
Prior to college, Mackenzi attended Morris Knolls High School (2016–2020), where she scored over 100 career goals. She was a three-time First Team All-County selection, two-time Brine All-American (NJ), and All-Star Warrior Team honoree.
Mackenzi brings high-level experience, leadership, and a passion for developing confident, competitive athletes.
ATIANNA DANZEY
Mid-Field- Triple Threat Elite | Dover HS | Montclair State University | USA Lacrosse Official
Atianna Danzey is a Mine Hill, NJ native and a USA Lacrosse official with over 10 years of experience in the sport. As a former midfielder for Renegades and various club teams, she transitioned into officiating to remain connected to the game when a competitive lacrosse program was unavailable at her high school. She currently applies that same leadership as a mathematics tutor and works for the Canfield Kids after school program.
Atianna attended Dover High School, where she graduated as Salutatorian with a 4.5 GPA and was named the 2024 Morris County Student of the Year. Athletically, she served as the captain and 2-time MVP of the girls volleyball team, 1st team All-NJAC and named the 2025 Morris County Scholar Athlete of the Year. She is currently pursuing her Masters of Business Administration in Finance at Montclair State University.
Atianna brings a unique blend of athletic discipline and academic excellence to her work, with a focus on developing confidence in the students and athletes she mentors.
KYLIE HEIMBACH
Goalie | Morris Knolls High School | Army (DI, Patriot League)
Staff member, Kylie Heimbach is a senior at Morris knolls high school. She will be attending the United States Military Academy next year to play division 1 lacrosse as a goal keeper! She volunteers as an EMT in her spare time and helps coach youth lacrosse.