He links up with compatriots Bernard Tekpetey, Nana Ampomah and 18-year-old Kelvin Ofori who signed on Tuesday.
"Fortuna Dusseldorf have loaned Kasim Adams for the upcoming Bundesliga season from TSG Hoffenheim," the Flingeraner announced on their official website on Thursday.
"The 24-year-old central defender is a Ghanaian international and gets back number 4.
"Adams will train for the first time this Thursday with the team."
Adams' first season with Hoffenheim was blighted by injuries, restricting him to 13 league appearances and 11 starts in the Bundesliga.
"I am very happy to be with Fortuna now," said the Accra-born player.
"I'll do my best to help the team in every training session and match.
"It will be important from the beginning [of the league on August 17] that we win games and score points to get closer to our goal of [avoiding] relegation bit by bit. We should concentrate fully on that."
"Kasim Adams is a centre-back with strong physical presence and header, which I know of very well through my time in Hoffenheim [as head of international relations last year]," Dusseldorf board member Lutz Pfannenstiel said.
"He was one of the best defensive players at this year's Africa Cup."
The Flingeraner open their Bundesliga campaign against Werder Bremen on August 17, a week after facing Villingen in the German Cup on Saturday.