Star Trek: 10 Reasons Wesley Crusher Needs His Own Spin-Off Series
7. Tau For Now
Speaking of who, just what are the Travellers really? The Traveller is the only member of the species we've (knowingly) met, and Wesley — Kore in training — the only other of the 'collective'. We've learnt more about them from Star Trek: Picard, and from Star Trek: Prodigy in particular, but there are still any number of questions as to the identity and origins of the OG from Tau Alpha C.
Super-duper-phasing-mind-power-time-space thing, possible addiction to colloidal silver, cranial bumps, different digits, slightly creepy, culturally insensitive use of shapeshifting, and a penchant for giant statues — that's about the extent of it for the Traveller's species. Even 'Tau Alpha C' as homeworld is confused, since Doctor Crusher gave "Tau Ceti" instead in Journey's End.
'Traveller,' in this case, is more properly the occupation and the organisation — "the interdimensional version of Starfleet," in Rok-Tahk's description. Humans can evidently be employed, but what exactly are the psychological and physiological requirements beyond 'is a very thoughtful genius'? A spin-off series could provide all the answers we need as to origins, agency, and rules of ascension. Well, that is, if all the other Travellers returned to the Prime universe post-Loom.