He spent the 2018/19 and 2019/20 campaigns with Besiktas in the Turkish top flight, playing 67 games with a return of just 14 clean sheets in that time.
A dispute over wages saw Karius terminate his contract prematurely early in 2020 before linking back up with the Reds over pre-season, where it was laid out to him that his future lies elsewhere.
The Reds put a reported price tag of £6 million on his head but there were no bites, leading the club to accept a loan switch in the hope of seeing his market value rise next summer.
And he will be plying his trade in the Bundesliga with Union Berlin, who do not have an option to make the switch permanent.
For all the criticism that has come his way over a turbulent last few years, there will be widespread hopes that he can continue to turn his career around and finally find a place to call home.
Karius will be returning to his native Germany, four years after leaving Mainz in 2016 to join Liverpool.
He will have one year remaining on his deal at the conclusion of the season, one which he will hope to play a key part in cementing Union’s place in the Bundesliga.
Meanwhile, academy goalkeeper Kamil Grabara has rejoined AGF Aarhus for the rest of 2020/21, having spent six months with the Danish side in 2019.
Best wish, Loris!