Warning: This list contains spoilers for the first three episodes of Hawkeye

Fans have been clamoring for Kingpin to join the MCU, and for Vincent D'Onofrio from the Daredevil Netflix series to reprise his role. It seems as though they may get their wish as there are many clues he is the big bad of the Hawkeye streaming series. The clues range from nods to the comic books to what appears to be a true cameo appearance in episode three of the new series.

RELATED: 10 Things About The Kingpin Only Comic Fans Know

The Kingpin is one of Spider-Man's greatest villains, but he has strong connections to the criminal underworld of Marvel Comics. The underworld is coming to the fore in the MCU in a big way in Hawkeye, and it seems that the show is positioning Kingpin in his traditional role as the head of the snake in New York City and likely beyond with some major teases in the new series.

The Presidential Hotel

Kate Bishop meets with Eleanor and Jack in Hawkeye series.

The location of the auction in the MCU is a major tell that Kingpin is the Big Bad of Hawkeye. Kate Bishop goes to The Presidential Hotel on the Upper East Side in Manhattan to meet with her mother Eleanor, and her fiancee, Jack. In season 3 of the Netflix Daredevil series, the Kingpin is relocated to The Presidential Hotel after agreeing to cooperate with authorities.

It's very possible that he is still based there in the MCU. The auction takes place in issue #4 of the 2011 Hawkeye series by writer Matt Fraction and artist David Aja but is actually set in Madripoor, one of the most important fictional Marvel Comics countries. Though Kingpin doesn't appear at the auction in the MCU series, the Tracksuit Mafia attack the auction, perhaps on the orders of the supervillain.

Echo

Echo from Marvel Comics.

One of the biggest pieces of evidence in favor of the Kingpin is the presence of Echo. In the comic books, Maya Lopez is Kingpin's adoptive daughter and one of his chief enforcers. Given her prominence in the story and other clues within the series, it seems likely this hasn't changed for the MCU.

Longtime comic book fans know Echo was adopted by Kingpin after the death of her father, who was one of his underlings. While the circumstances of her father's death have changed in the MCU, her family connections might not have.

Kazi The Clown

Kazi sitting down

There are some major differences between the Hawkeye comics and the show, but one of the constants is the connection between the Tracksuit Mafia and Kazi The Clown. Comic book fans know Kazi has worked for Kingpin in the past. In the streaming series, he makes references to Maya's 'uncle,' a figure fans get a glimpse of in episode three.

The series makes repeated references to their leader in the first three episodes, without naming them. It's a clear setup for someone significant, and other clues point to the Kingpin being the man behind the curtain.

The Death of Echo's Father

Echo loses her father in Hawkeye series.

Echo is an enforcer for Kingpin in the comics, but he actually killed her father himself. In the MCU, it's Ronin. Ronin's involvement would seem to preclude Kingpin, but it's Kazi's reference to Maya's uncle in episode three that provides another clue to his role in the series.

Kazi suggests Maya's uncle is not happy with what the gang is doing regarding Ronin, and that could be because the Kingpin is actually behind the death of Maya's father. He may have solicited Ronin to do it, with Clint thinking at the time that Wilson Fisk was reformed. Another possibility is Clint didn't know exactly who benefitted from his actions as Ronin.

"Someone Above Maya"

Blended image of Maya Lopez aka Echo in Hawkeye and Kingpin Wilson Fisk in Daredevil

The references to the boss of the Tracksuit Mafia become more pointed in episode three of the series. After narrowly escaping the Tracksuit Mafia and Echo, Clint Barton and Kate Bishop discuss the hierarchy of the gang. Clint makes it clear that there is "someone above Maya."

RELATED: 10 Most Powerful Villains Of Kate Bishop's Hawkeye

The series seems to be building toward the reveal of a big bad with each episode, first hinting at a singular survivor of Ronin's attacks on the underworld in episode one, then suggesting Echo was, and now making clear she reports to someone else.

Vincent D'Onfrio Tweets

Social media isn't always the best barometer of what might happen in MCU movies and shows, with rumors running rampant. But Vincent D'Onofrio added fuel to the fire by commenting directly on the Hawkeye series. He retweeted a trailer for the show, saying he "loves these Marvel shows."

While he could very well just be a fan, it's still a high-profile case of fandom for D'Onofrio, who played Wilson Fisk in Daredevil. He has also commented directly on the rumored concept art of Kingpin in other tweets.

NY1 News Anchor

Pat Kiernan reports for NY1 News in Hawkeye.

Another tangential clue from the Netflix series is the presence of Pat Kiernan, a reporter for NY1 News who makes appearances in the Hawkeye series. He also made numerous appearances throughout the Netflix suite of Marvel shows, including commenting on Wilson Fisk in season 1 of Daredevil.

RELATED: Kate Bishop's Hawkeye And 9 Other Badass Female Archers In Comic Books

While it may not be concrete proof of the Kingpin - Kiernan has made appearances in Spider-Man: Far From Home as well - it's another obvious connection to the Netflix series that the MCU didn't have to make.

Fat Man Auto

Echo pulls up to Fat Man Auto in Hawkeye.

While not the kindest of references, it seems as though there is a possible one to the Kingpin in episode three. In the flashback that opens the episode, Maya arrives at the auto garage her father works at to find it being attacked by Ronin (also making clear she was a Snap survivor). The name of the shop is Fat Man Auto Repair.

Comic book fans know Kingpin is one of the best Spider-Man villains because of his impressive size and strength. Spider-Man sometimes throws some verbal jabs at him over it, and that could be reflected in the name of the auto shop.

Maya's 'Uncle'

A man pinches young Echo's cheek in Hawkeye.

The episode three flashback seems to feature the first cameo appearance of the Kingpin in the MCU. While training in martial arts as a girl, Maya Lopez meets her 'uncle.' This uncle is a towering figure wearing a black suit. The viewer never sees his face, but he pinches her cheek and she smiles in appreciation.

Kingpin wore black suits in Daredevil, and the build of the character seems to line up very closely with that of Vincent D'Onofrio. It's telling the series doesn't show his face here, but they do give something else away.

That Voice

Kingpin looking straightfoward in Daredevil marketing

Maya's 'uncle' says nothing in the flashback, but he does laugh kindly as he pinches her cheek. While it's not credited, the laugh seems to belong to Vincent D'Onofrio. The actor's distinctive voice is a very close match for the brief bit of audio in the episode.

Time will tell if it's actually him, but the inclusion of the voice and the visual appearance of a Kingpin-line figure represent the most obvious clues yet that Wilson Fisk is the big bad of Hawkeye and now a major part of the MCU.

NEXT: 10 Best Versions Of Hawkeye From Marvel Comics