Despite a couple of teaser trailers, details remain scarce about "Iron Fist," Netflix's fourth Marvel drama, following "Daredevil," "Jessica Jones" and "Luke Cage." However, star Finn Jones, who plays Daniel Rand, took to Instagram to tease a possible appearance by another Marvel Comics character: Lei-Kung the Thunderer.

A photo posted by Finnstagram (@finnjones) on

Debuting just after Iron Fist, in 1974's "Marvel Premiere" #16, Lei-Kung is an immortal martial arts master in the mystical city of K'un-Lun, where he's charged with training its inhabitants in the art of kung-fu. While the inclusion of the character on the Netflix series isn't confirmed, it would make perfect sense, as he was Daniel Rand's first trainer.

In the comics, Lei-Kung trained multiple generations, including Daniel's father Wendell, who eventually defeated the Thunderer's son Davos. Davos eventually becomes the recurring enemy of Wendell Rand and Daniel Rand, and could possibly factor into the Netflix series' future.

All we know of the Iron First series so far is that Danny Rand returns to New York after his mysterious disappearance and puts his newfound martial arts abilities to use while quelling the city's criminal inhabitants.

Filming for "Iron Fist" began in April New York City. The series is scheduled to debut in 2017.

(via Cinemablend)