Through the likes of the Professor, Nairobi, Tokyo, and Berlin, Money Heist introduced a compelling cast of core characters in its first season. When the second heist began in the show's third season, many new characters began to be added to the story.
While most of the new additions didn't reach the popularity of most of the original characters, they still managed to be intriguing in their own right. Each of the new characters brought new challenges and thrills, especially as Money Heist built toward its exciting and memorable series finale.
César Gandía
Gandía's ruthlessness and military experience made him a genuinely formidable threat. He will be forever hated for the brutal and unforgivable murder of fan-favorite Nairobi. He will also be forever remembered for being taken out in a selfless and satisfying fashion by Tokyo, (which is one of the best things she ever did on Money Heist).
While Gandía was a truly intimidating villain brought to life by José Manuel Poga's chilling performance, he was a bit of a one-note character as there wasn't much to him other than being a merciless and arrogant villain.
Benito Antoñanzas
The Professor blackmailed law enforcement officer Benito Antoñanzas (Antonio Romero) into helping him. Thanks to Benito, the Professor learned where Lisbon was being held and was able to communicate with her while she was held by the authorities.
Even though he was frequently worried about being caught, Benito did a good job of staying under the radar and helping Lisbon and the Professor (even if it was against Benito's will). One of the most impressive things about him was that by the end of the series, he was never caught by Tamayo or any of the other authorities. He felt like an honorary--albeit involuntary--member of the gang.
Luis Tamayo
Colonel Tamayo (Fernando Cayo) was even more detestable than Colonel Prieto from the first heist. Not only was Tamayo willing to kill and stop the gang at any cost, but he had no qualms about throwing his colleagues under the bus to save his own skin.
Even though Tamayo was repeatedly flummoxed and duped by the Professor and the gang, no one could ever feel bad for him because of the contemptible way he talked and treated others. In fact, there was something highly entertaining and satisfying about seeing such a selfish and corrupt individual losing control of his emotions and at a complete loss of what to do after being continuously outsmarted. He is a villain fans loved to hate.
Tatiana
After mentions of Berlin's numerous ex-wives during the first heist, it was satisfying to finally meet one of them in the flashbacks. Tatiana (Diana Gómez) was filled with the kind of passion, joy, hunger for danger, and appreciation for the finer things that made her seem like a perfect match for Berlin.
Knowing that she was Berlin's last ex-wife surrounded her story with an air of eventual doom and mystery. This initially paid off when she left Berlin for his son Rafael and again when she and Rafael emerged in the present-day storyline to steal the gold from the Bank of Spain heist.
Benjamín Martínez
Unlike most of the new characters who debuted in season 3, Benjamín Martínez (Ramón Agirre) wasn't introduced until the second-to-last episode of season 4. Despite his late introduction, Benjamín became a memorable and important character. Benjamín was a good friend of Moscow's and, eventually, a very supportive father to his daughter Julia.
During the Bank of Spain heist, Benjamín proved to be an invaluable member of the gang when he played an important role in freeing Lisbon from the authorities in season 4. When the Professor was unable to be at the stormwater tank when the melted gold was transported there in season 5, Benjamín led the operation and ensured that all of the gold was reforged back into ingots.
Palermo
Berlin's death left a gaping hole in the gang. Palermo (Rodrigo de la Serna) did his best to fill this hole by leading the gang inside the Bank of Spain. Like Berlin, Palermo was a romantic who was also a pragmatic leader and ruthless when he needed to be. Palermo could be infuriating (such as the storyline Money Heist fans hated when he freed Gandía after having his leadership usurped).
Yet, fans couldn't help but feel bad for Palermo and his story of unrequited love for Berlin. Moreover, Palermo came up with some of the most brilliant and effective parts of the Bank of Spain heist and he provided the tough leadership that was necessary for most of the gang to survive and get the gold in the end.
Marseille
Of Berlin's old friends who joined the second heist, Marseille (Luka Peroš) was easily the most likable of them. A lot of this came down to Marseille always being loyal and reliable and never stirring up drama and conflict like other members of the gang. When the Professor thought Lisbon was dead, Marseille was the voice of reason who comforted the Professor while also keeping him focused on the heist.
No matter what the Professor asked of Marseille, he always rose to the challenge and helped the group. It was refreshing to have such an active and dependable member of the heist outside the Bank of Spain, always ready to help the Professor and the group.
Rafael
At first, it seemed strange for the final season of Money Heist to introduce Berlin's son, Rafael, (Patrick Criado) through flashbacks. It seemed too late in the game to introduce his character and it was unclear for a while why the final season was spending so much time focusing on him.
All of this paid off when Rafael surfaced in the present-day storyline when he stole the gold after it was transported out of the Bank of Spain. By stealing the gold without doing any of the hard work and by stealing Tatiana's heart, Rafael became the kind of man Berlin wanted him to be (but at the cost of hurting the Professor and the legacy of Berlin). However, Rafael did prove to be honorable in the end as he was convinced to give back the gold to the Professor and the gang.
Manila
Julia/Manila (Belén Cuesta) became one of the gang's most valuable members inside the Bank of Spain. She pretended to be a hostage so she could observe the other hostages and prevent them from causing any trouble. While she was able to fly under the radar for all of season 3 and most of season 4, she was forced to blow her cover toward the end of season 4 when Arturo ambushed Matías and took his gun.
Manila stopped Arturo--a character who got worse and worse--from shooting anyone and igniting a hostage revolt. While helping the gang survive in season 5, Manila grappled with her long-held romantic feelings for Denver in an honest way, ultimately realizing she didn't actually love him in that way anymore.
Alicia Sierra
Thanks to the performance of Najwa Nimri, Alicia Sierra became Money Heist's best character introduced after season 1. From brutally torturing Rio to using Nairobi's son as bait that would allow Nairobi to get shot, Inspector Alicia Sierra quickly proved to be a calculated and merciless individual willing to do whatever she thought necessary to stop the Professor and the rest of the gang.
When Tamayo and her other colleagues tried to make her take the fall for all the authorities' crimes, Sierra evaded capture, found the Professor, and took him captive. Despite her best efforts to resist, he eventually got to her and she decided to use her skills for herself, her baby, and the people who valued her. Sierra was the one who figured out where Rafael and Tatiana hid the stolen gold and got them to surrender it. She went from being one of Money Heist's biggest villains to having one of the best redemption arcs.