Long-serving Borussia Dortmund forward Marco Reus is to leave the club at the end of the season, ending “an extraordinary era,” the Bundesliga team said on Friday. “Borussia Dortmund and their long-term captain Marco Reus have mutually agreed not to extend the player’s contract, which expires at the end of the season,” Dortmund said in a statement. The Dortmund native has been at the club for 12 years since returning in 2012. Considering his time at the youth academy, Reus spent a total of more than 21 years at the club. He played a crucial role in leading Dortmund to the Champions League fina…