Though Eidolons had become an unofficial force within the tuluan military long before the turian Hierarchy angrily went after them for activating all the mass relays within their space, when they were faced with the existence of many other species - most of whom didn’t jive with their culture - the tuluan Union wordlessly began actively appointing Eidolans.

Picking the most promising military recruits and individuals with a personal flare and evidence of grand potential that ping on individual members’ radar. Eidolons receive no official training prior to their appointment and though their existence is known about throughout tuluan space, no Eidolons are known by name and there is no officially kept record of the number of Eidolons in operation.

Despite their lack of training, there is a wordless bottom-line that Eidolon perspectives are expected to meet;

They must be fluent in at least two xeno-languages without the use of a translator excluding languages of their own species.

They must be comfortable walking the line between law enforcer and fugitive, understanding that there will be times that the Union cannot and will not protect them.

They must prioritize the safety and sanity of those incapable or merely less capable of protecting and defending themselves over those that can and especially over those of law enforcement

They must be willing and capable of making hard choices when defending the innocent and vulnerable, willing to bloody their hands to preserve others

Everything an Eidolon touches is liable to wrapped in red tape and scoured with a black-out marker, filed under the agent’s codenames. Despite all this, Eidolons do have a biochip that is untraceable by most technologies that operate as a form of digital badge when encountering other Eidolons who possess the only readers of this information. The tuluan Union isn’t stupid either and ensure that each recorded code-name has all the missions that agent was on and if there’s proof that an agent is going rogue, another Eidolon is sent after them.

In order to maintain a decentralized rule of Eidolons, not everyone in the Union knows most or even many Eidolons. It’s generally accepted in fact that you will only know the Eidolons you coined and any that chose to work alongside them. This was  the problem the Citadel Council ran into when they discovered the first Eidolons who were operating outside the Paradise Systems and tried to demand the identities of all current Eidolons. When the Eastern wing head, Ahat flatly informed them that she knew of exactly one Eidolon - who was dead - they switched gears and instead pressured the tuluan Union into accepting the SPECTERs and Eidolons’s Agreement.

The agreement dictates that the Citadel Council can direct and give missions to Eidolons as if they were SPECTEREs and within Citadel Space, obeyed Council laws. If a rogue Eidolon begins causing galactic wide problems, the Citadel is allowed to punish them - up to and including, stripping them of their Eidolon status. Though the agreement was signed, there is still some lingering resentment from the Paradise Systems towards the Council about this considering the Asari Justicars were left relatively untouched by Council law.

Eidolons are officially classified as a sub-branch of SPECTERs in the Council databases and all information about Eidolons is suffocated and hidden for fear that the other races - particularly the Krogan despite their own lack of centralization - may follow in their lead with high-flying secret agents.