Nicolas Castillo has developed a cult following with Pumas UNAM in Liga MX

MEXICO CITY -- Among the passionate spectrum of fandom for Mexico's Liga MX clubs, those who follow Pumas UNAM have consistently been among the most devoted.

As such, it wasn't entirely surprising when a fan decided to tattoo striker Nico Castillo's likeness on his arm. What is surprising, however, is the context behind the decision. It has been less than nine months since the 24-year-old Castillo arrived in Mexico.

Off the pitch, the stocky striker looks harmless: constantly smiling, generally amiable with fans and press alike. On the pitch, however, Castillo's style is rough, powerful and aggressive.

He has also been quite effective. In just 17 league games with the Mexico City side, Castillo has already notched 13 goals. Embracing the pressure of playing in front of the home crowd, the Santiago-born striker has relished the opportunity to play at the Estadio Olimpico Universitario, scoring all but one of his goals there.

His importance to the club cannot be overstated. Castillo has scored nearly half of his team's 27 goals since arriving in January. Four of those have come against Club America and Cruz Azul, two of Pumas' top rivals.

The Jekyll-Hyde combination of Castillo's personality has meant an instant love affair with fans of the seven-time Liga MX champions. His teammates have fawned over him, too.

"We've depended on him. He's scored the goals, and we hope he keeps going because he's an important player," defender Josecarlos Van Rankin said earlier this month.

Pumas' last title came in 2011, when recently fired coach Francisco Palencia was playing for the side. In 2015, they were famously denied in the final following a dramatic penalty shootout with Tigres.

Although Palencia coached the team to the playoffs in the Apertura 2016, last season's side failed to crack the postseason. Following a summer in which Pumas did not have meaningful signings, the team's notoriously passionate fans are losing patience.

Pumas fans had loudly called for the ouster of Palencia toward the end of a disappointing loss at home against Morelia on Tuesday. The team announced Wednesday that Palencia was out and that Sergio Egea would take over in a temporary capacity.

Such instability is common in Liga MX and not necessarily damning. The season is still at a point in which a substitute can come in and help steer a team toward relevance.

Regardless of who is at the helm, it is clear that Pumas will rely strongly on their star striker moving forward. Knowing full well that his stay in Mexico could be briefer than expected, the rising cult of Castillo among fans is curious and notable.

Originally acquired from Belgium's Club Brugge following a loan spell in Chile, Castillo's form and overall potential signified a coup for Pumas when the deal went through. His subsequent performances during the Clausura 2016 and current Apertura 2017 have prompted other clubs around the league to double down on Castillo's compatriots.

There's already a notable wave of Chilean players currently filling Liga MX rosters. Despite his relative newness to the circuit, Castillo is arguably the best right now. Although many of the imports have performed admirably, the striker's age and quick domination of the league have prompted speculation that he'll move on next summer, should he be selected to Chile's World Cup squad.

"There's a clause in my contract that allows me [to go to Europe]. I've always wanted to go back," Castillo said in June. The stated declaration puts a time crunch on Pumas' ambitions to transcend in the league with Castillo.

Already drawing interest from the Spanish and Italian leagues, Castillo's growing role within the team might spawn pressure to deliver silverware to the fans of this stagnant league giant before he parts.

Although Castillo's stay at Pumas and Liga MX might prove to be temporary, his impact with fans -- and one in particular -- seems built to last.