It is not possible to provide a definitive answer to the question of the โMilitaryโs most secret unit,โ as such information is classified and not publicly available. In a thread on Quora, a retired US Army Special Forces officer and enlisted soldier, who has served at various levels and locations, offered some insights into the subject. It is worth noting that the Central Intelligence Agency (CIA) is not affiliated with the US Department of Defense and therefore is not a military unit. Any discussions about CIA units and missions should be considered speculative at best.

The officer also defined โmost secret,โ which goes against the questionโs premise because it asks for the โMilitaryโs most secret team.โ He stated that โmost secret teams are most probably.โ However, this is not a factual, evidence-based answer but rather a conjecture. It is also worth noting that the term โunderhandedโ is not a military term; therefore, its meaning is unclear.
In discussing some of the more well-known units in the Special Operations Forces (SOF) community, the officer noted that both Delta Force and US Navy SEAL Team 6 are not considered intelligence teams. Delta Force has never been referred to as a team, while SEAL Team 6 has been referred to as a team due to its original name. It is important to understand the differences between the terms โDirect Actionโ and โAssaultโ as they are used in SOF missions. โDirect Actionโ missions do not include hostage rescue, a separate mission. โDirect Actionโ is not interchangeable with โAssault,โ and there is no such mission as an โAssaultโ mission in US SOF.

Many of the answers in the thread referenced the ISA (Intelligence Support Activity). However, it is worth noting that they are not a military unit but rather falls under JSOC (Joint Special Operations Command) and are not a Tier 1 Special Mission Unit. They have been known by the identifier โGREY FOXโ among others in the past 20 years.