Mass Effect Andromeda is set in a completely different galaxy to the series' original trilogy, but that won't stop one minor character from returning.
Remember Avina? She was the Citadel's virtual intelligence character, and one of the few NPCs to appear in all three games.
Avina will return in Andromeda aboard the Nexus, the new central spacestation built as a deliberately Citadel-esque hub. She's voiced by the same actress as well, Dannah Feinglass.
You can hear her return in the latest Andromeda Initiative video, which details the various areas of the Nexus.
The station will contain your standard Mass Effect nightclub, shops, an area for Pathfinders of various races to meet, and a cultural sector with information on all the Milky Way races. Perhaps here we'll see some of the aliens not yet physically in Andromeda represented.
Surprisingly, the Nexus does not arrive intact. You'll be tasked with aiding the second phase of its construction when you arrive in Andromeda. It'll grow as you progress through the game.
So far, Avina is the only character to make a return from the original trilogy.
Andromeda begins just before Mass Effect 3, when the group of Milky Way ships leave the galaxy, and picks up 600 years later upon their arrival.