The biggest Bundesliga deals of the January transfer window

After a decade away, Sandro Wagner has returned to Bayern after Hoffenheim accepted a €13 million ($16 million) bid. Most feel Wagner will act as a back up to Robert Lewandowski, but he's not short on confidence. "In my eyes I’m the best German striker," Wagner said after scoring against Hoffenheim on Saturday. "I’m with the best team in Germany, scored a goal, and so I’m where I should be."

Wagner's wasn't the only homecoming for a veteran Bundesliga striker, with Gomez heading back to the club he left in 2009, after coming through the ranks. The German target man moved from Wolfsburg for a fee of €3 million and forced Hertha Berlin's Niklas Stark in to an own goal that handed Stuttgart a 1-0 win on his debut. He still harbors hopes of a World Cup berth.

Mainz signed a man famous for his role in a World Cup final, with Dutch enforcer Nigel de Jong likely to always be remembered for his kung fu kick on Xabi Alonso in the 2010 final, which Holland lost to Spain. The 33-year-old spent three years at Hamburg from 2006 to 2009 but joined Mainz on a free after a difficult time at Galatasaray, where he fell out with the coach.

Every transfer window has its saga and this time it was Pierre-Emerick Aubameyang to Arsenal. The 28-year-old's relationship with Dortmund had become untenable after a series of disputes and the Premier League club offered the prolific Gabonese forward a way out. He took it, along with a reported €205,000 a week salary.

Borussia Dortmund were determined to line up cover before letting Aubameyang leave. After some shuffling in London, with Arsenal's Olivier Giroud preferring to stay in the city and move to Chelsea, Belgian striker Michy Batshuayi will fill the gap on loan. Aged 24 but by no means a regular at Chelsea, Batshuayi will want a strong spell in the Bundesliga, seeking a World Cup ticket.

After a difficult and emotionally draining spell that included being injured in the Dortmund bus attack, Marc Bartra moved back to his native Spain. The center back's form has dipped since the attack and Dortmund chiefs said they were happy to offer him the fresh start he felt he needed. Betis paid €10.5 million for the former Barcelona man.

Bartra's replacement actually joined Dortmund before the Spaniard's departure. Swiss center back Manuel Akanji enjoys a growing reputation after a string of impressive performances for Basel, both in Switzerland and in the Champions League. The 22-year-old has been an unused substitute in both Dortmund's Bundesliga fixtures since joining.

True to their transfer form, RB Leipzig have looked to youth for their only signing of the window. The Red Bull-backed club have signed highly-regarded Danish youth midfielder Mads Bistrup, 16, from Copenhagen. The Danish club said Leipzig's offer of €2.5 million was too good to turn down for a player who is yet to make a senior club appearance.

The first Bundesliga deal of deadline day belonged to Wolfsburg, who captured Admir Mehmedi from Bayer Leverkusen. The Switzerland international has struggled for gametime this term, with Leon Bailey, Kevin Volland and Lucas Alario keeping him out of the side. He's signed a deal until 2022 and could make his debut at home to Stuttgart on Saturday.

One man who has already made an impression on Germany's top flight is Marko Pjaca. The attacking midfielder joined the Royal Blues on loan from Juventus until the end of the season and scored against Hannover on his second substitute appearance for his new club.

Another January signing to have an impact is Simon Terodde. The frontman scored a dramatic late winner against local rivals Borussia Mönchengladbach on his debut and followed it up with a brace against fellow strugglers Hamburg in a 2-0 win. Those strikes mean Cologne, who didn't win for the first 16 games, are now just four points from the relegation playoff spot.