Regular Army

The Regular Army is a military organization located in many places of the world.

Peregrine Falcons

 * Marco Rossi (Leader)
 * Tarma Roving (Commander)
 * Trevor Spacey (Commander)
 * Tyra Elson
 * Gimlet

S.P.A.R.R.O.W.S.

 * Eri Kasamoto (Leader)
 * Fio Germi (Master Sergeant)
 * Nadia Cassel (Private)
 * Red Eye (Any rank that is found in Metal Slug 1st Mission and 2nd Mission)

Ikari Warriors

 * Heidern (Leader)
 * Ralf Jones (Colonel)
 * Nathalie Neo
 * Clark Still (Major)
 * Leona Heidern (Private)
 * Roberto Nicola
 * Whip (Staff Sergeant)

Other Members/Relatives

 * Rumi Aikawa (Sergeant and Supplier)
 * Madoka Aikawa (Private and Supplier)
 * Hyakutaro Ichimonji (2nd Lieutenant)
 * Tequila (Cover Agent)
 * Alisa Stewart (Engineer)
 * Midori (Junior Engineer and Mechanic)
 * MS-Alice (Regular Army's A.I. created by Marco)
 * Matilda (Scientist)
 * Navel
 * Selina (Merchant and Supplier)
 * Mello (Future Soldier, commander of future Regular Army in Metal Slug 13)
 * Rita
 * Amber
 * Perche
 * Nikita
 * Reika
 * Vanessa (Hired by Heidern)

Drill Instructors

 * Sophia
 * Margaret
 * Lilly
 * Mary
 * Cynthia

Game Ideas Appearances

 * Metal Slug 8
 * Metal Slug 8
 * Metal Slug 8
 * Metal Slug 9
 * Metal Slug 1X0
 * Metal Slug 11
 * Metal Slug 12
 * Metal Slug 13
 * Metal Slug 14
 * Metal Slug Fighters
 * Metal Slug Anthology 2: The War Continues
 * The King of Fighters XV
 * The King of Fighters XV (TheProjectXZoneFan1997)
 * The King of Fighters 15
 * The King of Fighters: Redux
 * Neo Geo 2: Match of the Century
 * Project X Zone 3: Sacred Destinies
 * Super X Dimensions
 * Divine X Union