49 years ago - Ti'julk Mr'asz is born.
37 years ago - 12-year-old Ti'julk's gating powers manifest.
31 years ago - 18-year-old Ti'julk is given over to the Citadel by his people. he is brutalized to have his gating ability surgically removed so that it's properties can be artificially copied. He is sent to be imprisoned in the Starlog.
19 years ago - 30-year-old Ti'julk's powers are surgically reactivated by Vril Dox, allowing them to escape. he joins L.E.G.I.O.N. despite his belief that all military forces are inherently fascist, taking the name Gates.
8 years ago - 41-year-old Gates, upon having his powers successfully replicated by Vril Dox, retires from L.E.G.I.O.N. to Hardcore Station.
Gates is actually traditionally a part of the 30th century Legion of Superheroes, but his main defining characteristic, beyond being one of the team's few non-humanoid members, is that he actually doesn't want to be there. He's a conscript from his home planet during a time when every planet is required to send members to the legion, but as a pacifist he's fundamentally against any sort of violence, even in service to the greater good.
We like the character, but he doesn't really fit into that team. However, moving him into the modern era and allying him with Vril Dox is a huge and immediate improvement. His gating powers are a huge deal for any sort of intergalactic organization, and they quickly make him a pawn in a larger game, making his pacifistic beliefs a functional character conflict as opposed to an inconvenience to the larger story. It creates a cool window for Vril to exhibit his brilliance to convince Gates to allow him to use his powers in a deliberately non-violent fashion, treating him as an ally instead of a conscript. Later, when Vril successfully reproduces his powers, Gates can retire, knowing he's helped his friend and still held true to his beliefs.