From Halopedia, the Halo wiki
Due to Recluse being a classified armor, a lack of ethical, legal and administrative oversight would allow hypothetical RECLUSE designers to fully exploit Spartan neurological peculiarities - albeit at great risk of inducing dangerous side effects.
The RECLUSE does not appear in any UNSC logistics tracking system, nor does it bare any manufacturing markings. It is a suit that doesn't exist, created for missions that never happened, by Spartans who never were.
Halo 5: Guardians
Unlock: Common REQ card
Available Skins: Laeta and Seri
List of appearances