The entire arena of 19,000 people erupted when Rusev appeared for his Royal Rumble entrance at the Wells Fargo Center. On their feet, they chanted "Rusev Day!" over and over, earning him the largest ovation of the night and continuing a trend seen at every WWE tour stop.

The once-hated heel now reps some of the most popular WWE merchandise, including his own calendar. He plays it cool on television, but he can't believe the way fans have received his latest efforts.

"I had no idea this was going to happen," Rusev said to ESPN. "This was supposed to be a one-time 'Rusev Day' thing. I never thought in a million years it was going to be what it is today. It was something we planned to do, but just for one day. But it just caught on fire ever since then. Nobody expected that."

Despite being a villain in the WWE universe since his debut, fans have clamored for Rusev since the creation of the gimmick. For the uninitiated, Rusev Day was a segment created to celebrate Rusev's victory against Randy Orton in October. He defeated Orton in a record eight seconds, and during his celebration the following week, he decided to call it "Rusev Day."

It caught on, and the cheers were definitely something new.

Chants of "Rusev Day" continued throughout Rusev's 30-minute stint in the 2018 Royal Rumble. Dave Moser for ESPN

"I've just been enjoying it," Rusev said. "I've been booed out of the building for the past four years. So finally the people now appreciate me. But I'm just having fun, I'm just doing me. Every bad guy or good guy, we all enjoy the crowd reaction, so I'm just going with it."

Rusev and his most recent associate, Aiden English, have been taking the efforts to new levels each time. Instead of bashing the crowd and country while waving a Bulgarian flag, the foreigner is singing and dressing up as Santa Claus.

"By far it's the most fun I've had in my career," Rusev said. "I mean, I loved WrestleMania 31 with the tank -- that was amazing, of course. But now I'm showing everybody that you don't have to be stuck being a foreigner bad guy. Being a foreigner bad guy doesn't have to be my destiny, and I can be much more than that."

Rewinding the clock to 2005, when a young Rusev had just moved to Los Angeles from Bulgaria in hopes of becoming a WWE superstar, Rusev was chasing the dream of his 6-year-old self, a young Hulkamaniac inspired to become a wrestler. Due to his being a foreigner with a heavy accent, he played the role of a bad guy since the first day of training.

"I had no idea how [wrestling] worked," Rusev said. "I just know that when I even trained in KnokX Pro, I played the foreigner there, too. I've just always been doing that. When an American person hears you speak a different language, you're automatically the bad guy. That's the box. I've been in that box since day one in training."

Rusev played that role as perfectly as one could have.

In Rusev's first two years as a stereotypical anti-American heel on the WWE roster, he was able to go undefeated for a year, enter WrestleMania 31 in a tank, then wrestle John Cena, share a segment with The Rock on Monday Night Raw and share a ring with Stone Cold at WrestleMania 32. He's one of very few members on the active roster who has been trusted to work with The Rock and Stone Cold, and he remembers the experience and the advice they offered.

"The Rock taught me you don't always have to talk or move all the time," Rusev said. "You can just stand there and soak it in. Let the crowd just do what they do. Looking back at the segment, I could tell what he was talking about.

"Austin actually punched me in the mouth so hard, he tore his shoulder. So he taught me to never punch someone too hard. I joke with him about it all the time."

Rusev made his entrance for his WrestleMania 31 match against John Cena on a tank. Courtesy WWE

Although Rusev is no longer playing that role, his portrayal was a necessary means to an end. It brought him his favorite experience in the WWE: the tank.

"The tank entrance at WrestleMania 31 is my favorite moment in WWE," Rusev said. "It's definitely a top five entrance of all time. Everything was just so perfectly executed. I rehearsed it the day before and had no idea it was happening before that. I always wished for years about a tank entrance in wrestling, and I feel like I manifested that at WrestleMania. I had to make sure I didn't burn my feet somewhere because I was barefoot at the time."

Rusev's journey to stardom is essentially an embodiment of the American Dream. He has gone from watching WWE VHS tapes in Bulgaria to living in America to working at Wendy's to becoming a celebrity.

"[The experience] has been a lot of long years, with a lot of obstacles along the way," he said. "But as long as I kept focus with my goal, nothing could stop me until I achieved it. You work hard, and the hard work pays off."

It might seem like Rusev Day is just a fun little gimmick, but it's something much more. In the history of wrestling, many foreigners have played the same role: Iron Sheik, Nikolai Volkoff and, most recently, Jinder Mahal. Rusev doesn't want others to be limited, as he has broken the mold of a foreigner's role. He doesn't want others to be limited to an angry, flag-bearing, one-note individual. That's the legacy Rusev wants to leave.

"When you look back at foreign wrestlers 20 years from now, you'll remember I wasn't like them," Rusev said. "I want to be remembered as the guy who broke that mold for other foreign wrestlers."

Wrestling is a business filled with challenges, and to those trying to follow in his footsteps, he explains that patience is key.

"Just do what you have to at first," he said. "When the time is right, show them who you are and what you can actually be. Don't be afraid. Pick your battles though, too. You can't always fight them."