Kaiserslautern fans typically greet opponents in their home grounds, Fritz Walter Stadium, by unfurling banners reading "Welcome to Hell." But on February 12, the Red Devils and their supporters turned the Bayarena in Leverkusen into an inferno, when they knocked one of Germany’s best teams out of the German Cup with a stunning 1-0 upset.

It was a result that warmed the hearts of many Bundesliga traditionalists. With their corporate sponsor, Leverkusen are often seen as an example of the commercialization of German football, whereas second-division Lautern – a founding member of the Bundesliga – is a club whose history is as long as its supporters fanaticism is deep.

The four-time German champions may have only spent two of past season seasons in the top tier, but they’ve never really disappeared from the consciousness of hardcore Bundesliga followers. In a recent poll conducted by Bild newspaper, in which fans were asked which clubs they would like to see in the top flight, Kaiserslautern came in thirteenth, one spot behind Leverkusen and only five behind Bayern Munich.

So why does a squad full of rejects from other clubs from a city of only around 100,000 inhabitants on the southwestern fringe of Germany occupy such a prominent place in the country’s collective footballing consciousness?

To answer that, you have to delve into the past. The Red Devils’ hard-fought but ultimately deserved upset of Leverkusen is just the latest highlight in a history overflowing with ups and downs.

A Postwar Success Story

In many respects, Kaiserslautern’s fate in the years after World War II mirrored that of West Germany as a whole. That conflict had cost the lives of a number of the team’s starting players, but 1945 saw the return of the man who would become synonymous with FC Kaiserslautern: playmaker and stadium namesake Fritz Walter.

They immediately came in second in their regional league, and national titles followed in 1951 and 1953. Walter and other Kaiserslautern players also formed the backbone of the West German national team that won the World Cup in the so-called “Miracle of Bern.” Athletically speaking it was that triumph – the first world championship ever for Germany – which put the country back on the map.

After the Bundesliga was founded in 1963, Kaiserslautern were part of Germany’s footballing elite for 33 years, and in 1990-91, the Red Devils finally claimed the Bundesliga title. Forward Stefan Kuntz was voted German player of the year.

But only five seasons later, the challenges of trying to maintain such a small-market club at the very top became all too apparent. Kuntz and other standouts left, and the team failed to compensate. In 1996, despite winning the German Cup, Kaiserslautern were relegated.

It looked like the beginning of the end. In fact, it was the prelude to probably the most remarkable Bundesliga comeback ever.

King Otto’s Reign

Shortly before the start of the 1996-97 season, Lautern appointed a Goethe-quoting coach in his late 50s with a reputation for arrogance – Otto Rehhegal – to lead the team in its first season in the second division. Pundits predicted that the marriage between Lautern and Rehhagel, whose was used to bigger and better things at former employers Bremen and Bayern, wouldn’t last long.

Not only did Kaiserslautern achieve promotion and top the second-division table in 1997. In 1997-98, the Red Devils won the first division ahead of Bayern Munich, leading the table from the fourth round until the end and becoming the only newly promoted team ever to capture German football’s most coveted prize.

But “King Otto” Rehhagel abdicated his position in 2000, and the Red Devils spent well beyond their means in an era where lots of bigger clubs tossed around millions in the attempt to lure top foreign talent. By 2006, they were back in the second division, where, with the exception of 2010-12, they’ve stayed.

Kaiserslautern qualified for the playoff last season and had the chance to return to top flight, but they were clearly overmatched against Hoffenheim, whose expensive squad is bankrolled by software magnate billionaire Dietmar Hopp’s billions.

Another golden opportunity

Kaiserslautern currently sits in fourth position in the division-two table, chances for promotion are slim. But even if they were to manage a last-ditch struggle into third place, their experiences against Hoffenheim taught the Red Devils that a playoff is not an easy match to win – particularly as this season’s third worst team in Bundesliga is likely to be one of the bigger clubs.

It is questionable whether players like Karim Matmour, Mo Idrissou and Olivier Occean are really first-division caliber.

And on Wednesday (16.04., 20:30 UTC) they are facing the best team in Germany, maybe in the world, in the Allianz Arena in Munich. It could be another standout moment in the history of a club that's equal parts heaven and hell .