21st Cerberus Commando Platoon
Active:	7 August 2158 CE - 7 May 2184 CE (wiped out) 18 August 2185 CE - 11 November 2185 CE
Organization:	Cerberus Commandos
Affiliation:	Cerberus
Type:	Platoon
Role:	Strike operations
Size:	50 commandos
Part of:	5th Cerberus Commando Company
Headquarters:	Facility ANTONY, Omega
Engagements:	Operation Marcher Quarian-Cerberus conflict Attack on Shelba Idenna incident
Commanders:	Snd Lt. Pel Ladges †

The 21st Cerberus Commando Platoon (21st CCP) was a Cerberus Special Forces special operations unit attached to the 5th Cerberus Commando Company commanded by Second Lieutenant Pel Ladges. The unit was formed at the Cerberus training facility on Cronos Station in the earliest days of the organization along with the rest of the 3rd Commando Battalion in mid 2158 CE, and later assigned as a strike operations unit deployed on Omega along with its sister unit, the 22nd. During its time operating on Omega, the 21st would take part in numerous raids, principal among them Operation Marcher in 2170 CE, where it eliminated a batarian slaver believed to be involved in the Sack of Mindoir, only to uncover intel regarding a larger batarian plot to bomb several cities on Earth, with the 21st successfully tracking down the staging area for the terrorists and storming it, killing everyone inside and destroying the base. In 2179 CE, Pel Ladges assumed command over the 21st, a man whose loyalty was of dubious quality, having once been a Blue Suns mercenary before joining Cerberus and essentially a hired gun. He proved this in 2184 CE when his platoon was responsible for the capture of Gillian Grayson, Kahlee Sanders, Hendel Mitra and Nick Donahue on Omega following their attempted escape from Cerberus on Grissom Academy, thanks to intel provided by Paul Grayson. Unbeknownst to Grayson, Ladges planned to sell them to the Collectors, being kept in the dark as to why the Illusive Man wanted them alive and wanting to sell them out of spite and to make a quick profit. This plan failed when a quarian pilgrim named Lemm'Shal managed to infiltrate the compound and helped his prisoners escape, taking them on a shuttle to the Migrant Fleet. Unintentionally, Lemm left his shotgun behind, which helped Paul Grayson deduce their location.

Not informing the Illusive Man of what had happened, Ladges chose to fix the situation himself by raiding the Migrant Fleet and recapturing his fugitives by force. Leaving the 22nd behind on Omega, Pel took the 21st, with Paul Grayson and quarian traitor, exile and ally Golo'Mekk, to Shelba where he hoped to use Golo to lure a quarian shuttle to the planet to be ambushed and captured. The ambush went as planned, with Pel himself killing the ship's captain and their two adjutants, before stripping them of their suits and using them as disguises to slip some of his men into the shuttle: once inside, the rest of the 21st, donning snow camo and tactical cloaks, emerged from their positions and attacked the shuttle while the impostors inside launched their own attack from within, quickly overwhelming the shuttle and leaving no survivors save the pilot, Hilo'Jaa, who was kept for interrogation in order to extract his countersign. Despite Hilo dying during the interrogation due to Golo's temper, the 21st successfully acquired the code and took the captured Cyniad to be outfitted with a short-range laser to scramble the Idenna's communications. On 7 May, the Cyniad, with the 21st armed and ready in the loading bay, approached the Fleet and made it past their defenses due to Hilo's countersign, and successfully served as a trojan horse to get onto the ship. Once the ship's communications were scrambled and the shuttle had landed, the 21st sprung from their positions and blew through the security detachment waiting for them, quickly storming through the ship as they spread out to cover more ground, slaughtering anything that moved in their path as they searched for Gillian. Despite the element of surprise and rapidly moving through the ship, the 21st were moving through unknown territory, and due to splitting up, became lost or boxed in, something the quarian defenders used to their advantage as they fell back to established defensive positions and held off their advance in chokepoints. Accompanied by the 12th Explorer Platoon under Tali'Zorah, who happened to be visiting the ship at the time, the quarian marines were able to stall the assault of the main body of the 21st, inflicting heavy casualties as the 21st tried to advance. With his unit scattered and disorganized and facing heavy resistance, Pel ordered a tactical retreat back to the hangar in an attempt to regroup and make a concerted push, but he was shot and killed in the process, failing to realize his own position had been outflanked, and the rest of his group fell back in an attempt to withdraw. Word of Paul Grayson's betrayal only convinced the new commander of the 21st, Pel's second-in-command, that the operation had failed and ordered a full tactical retreat to the Cyniad to try and cut their losses and escape. This only helped the quarians box in the remaining commandos, and once they reached the shuttle, they were met with marines inside, who had waited for them. Most of their platoon wiped out, the remaining commandos dropped their weapons and tried to surrender but the quarians, enraged by the brutal and merciless killing of their civilians, among them children, showed no mercy and executed those who surrendered, leaving no survivors and effectively rendering the 21st wiped out.

The 21st was reformed in mid 2185 CE following its destruction at the Idenna incident, assuming its previous operations. In late 2185 CE, the unit was reorganized into a platoon of the APOLLO brigade, being renamed the 4th APOLLO Platoon.