Delta Recruit event is back for Star Trek Online. If you play an missed it last time they did it (3 years ago), I'd highly recommend logging in and doing it. Short version: You're creating a new character to provide account wide unlocks for all your other current and future characters. For maximum rewards you want to create one new character for each faction (FED/KDF/ROM), but one toon is sufficient for most of the rewards. You do not need to max them out during the event, simply progress them far enough to get the Delta Recruit flag, which is at the end of the tutorial which for some reason they are forcing you to play. There is a slight incentive to play them while the event is ACTIVE though (dilithium for killing enemies). You can delete the extra characters once you're done.
Full reward list is here:
https://www.arcgames.com/en/games/star-trek-online/news/detail/9116343
Between Delta Recruit and Temporal Agent (later similar event), that gets you roughly 500 fleet marks and 2,500 reputation marks for free on every toon you ever make once you hit 50. Suspicion is with the upcoming expansion this summer there's probably going to be a 3rd one of these events at that time.