Marcel Barthel (born 8 July 1990) is a German professional wrestler. As of 2017^[update], he is signed to WWE, where he performs on the Raw brand and in partner promotion Lucha Libre AAA Worldwide (AAA), as the masked luchador El Grande Americano. He is the leader of the Los Americanos stable.

Barthel previously wrestled under the ring name Axel Dieter Jr. in Germany, most notably for Westside Xtreme Wrestling (wXw), where he became a two-time World Tag Team Champion and one-time Unified World Wrestling Champion. He also wrestled in the UK for Progress Wrestling. He signed with WWE in 2017 and was assigned to NXT under his real name, Marcel Barthel, joining the Imperium stable where he won the NXT Tag Team Championship twice with Fabian Aichner. Imperium was moved to the main roster on SmackDown in 2022 where Barthel was renamed as Ludwig Kaiser, and then moved to Raw in 2023. From early 2025, Chad Gable had originally portrayed El Grande Americano, but due to injury, Barthel assumed the role on June 30, 2025. As Americano, Barthel is a former one-time WWE Speed Champion, a reign he had inherited when he took over the role from Gable.

Marcel Barthel was born 8 July 1990 in Pinneberg, Germany. He is a second-generation professional wrestler; his father, Axel Dieter (1933–2015), was later at ringside for his championship win in Westside Xtreme Wrestling (wXw) when he became one-half of the wXw World Tag Team Champions. His father was also a child soldier during World War II, fighting first for Nazi Germany before defecting to France, all before he was 12 years old. He later joined the French Foreign Legion.

Barthel was trained by his father Axel Dieter, Christian Eckstei, and Karsten Kretschmer. He debuted under the ring name Axel Dieter Jr. at NFC New Years Fight Night II on 1 March 2008, wrestling Da Mack to a time limit draw. He made his debut for Westside Xtreme Wrestling (wXw) in January 2009, losing to Dan Marshall. He did not have his next match in wXw until July 2012, when he and Da Mack defeated Walter and Michael Isotov. Dieter and Da Mack would go on to form a regular team, dubbing themselves Hot & Spicy. On 16 November 2013, they defeated The AUTsiders (Walter and Robert Dreissker) to win the wXw World Tag Team Championship. Dieter and Da Mack made seven successful defences of the championship, defeating the likes of The Sumerian Death Squad (Tommy End and Michael Dante), Forever Hooligans (Rocky Romero and Alex Koslov), and Kazuki Hashimoto and Ryuichi Kawakami. They lost the championships to Matt Striker and Trent? on 15 March 2014, but won them back in a rematch the following day. On 6 April, Dieter received his first opportunity at the wXw Shotgun Championship, losing to Axel Tischer. After over a combined year as wXw World Tag Team Champions, Dieter and Da Mack were defeated by French Flavour (Lucas Di Leo and Peter Fischer) on 18 October, bringing their reign to an end.

On 22 November 2014, Dieter unsuccessfully challenged Walter for the wXw Unified World Wrestling Championship. In February 2015, he took part in the Four Nations Cup, defeating Timothy Thatcher in the final to win the tournament. In March, Dieter took part in the 16 Carat Gold Tournament, defeating Zack Sabre Jr. in the semi-final to advance to the final, where he lost to Tommy End. In October, after a short break, Hot & Spicy teamed together once again and made it to the semi-finals of the 2015 World Tag Team Tournament before losing to reDRagon (Kyle O'Reilly and Bobby Fish). In March 2016, Dieter once again took part in the 16 Carat Gold Tournament, defeating Drew Galloway in the semi-final to advance to the final, where he lost to Sabre, the man he defeated to advance to the final in the previous year's tournament. On 2 September, Dieter and Da Mack faced off against each other, with Da Mack coming out on top and retaining his wXw Shotgun Championship. In late 2016, Dieter joined Ringkampf, and on 10 December, he defeated Marty Scurll to win the wXw Unified World Wrestling Title. Dieter held the championship until March 2017, when he was defeated by Jurn Simmons. In April, Dieter announced that he would be leaving wXw to pursue further opportunities outside of Germany. On 30 April, wXw held a farewell show for him, titled Die Matte Ist Heilig: Farewell to Axel Dieter Junior. In his final match as a full-time member of wXw, he teamed with Ringkampf stablemate Walter to defeat his long-time partner Da Mack and his long-time rival Simmons.

Due to wXw's working relationship with WWE, Barthel was able to make occasional appearances for the promotion. At the 17th Anniversary Show, in an untelevised segment, Barthel and Alexander Wolfe saved Walter and Thatcher after they were ambushed by members of the Rise stable. On 30 October 2018, it was confirmed that Barthel, under the Axel Dieter Jr. name, would return to wXw as a part of their 18th Anniversary Show on 22 December. At the event, he teamed with Walter and Thatcher to defeat British Strong Style (Pete Dunne, Trent Seven and Tyler Bate). In March 2019, he participated in the 16 Carat Gold Tournament, defeating Marius Al-Ani in the first round, before being eliminated by Lucky Kid in the quarter final. On the third night, he reunited with Da Mack, where they defeated Jay FK (Jay Skillet and Francis Kaspin).

On 23 November 2024, at Broken Rykes, Barthel (as Ludwig Kaiser) returned to wXw for the first time since 2019.

Representing wXw and Ringkampf, Dieter made his debut for Progress Wrestling in the UK on 15 January 2017, alongside Walter, defeating The London Riots (James Davis and Rob Lynch). They returned to the promotion on 29 January, losing to The South Pacific Power Trip (TK Cooper and Travis Banks). They once again returned on 19 March, defeating The Hunter Brothers (Jim and Lee Hunter). In his first singles match, Dieter lost to Mark Haskins. On 23 April, Dieter, Walter, and Timothy Thatcher unsuccessfully challenged British Strong Style (Pete Dunne, Trent Seven, and Tyler Bate) in a six-man tag team match for all of British Strong Style's championships.