Reporters have been hitting up Luke Cage actor Mike Colter pretty frequently for any and all details regarding The Defenders. For the most part, he's been pretty good about only teasing and revealing what little he can, but he apparently slipped up recently and revealed a previously unannounced returning villain from the other MCU shows. Colter was with Finn Jones at a panel for Comicpalooza in Houston when he accidentally confirmed a particular Daredevil villain as being in the recently released Defenders trailer, who wasn't actually in the trailer:
We saw Madame Gao [in the trailer]. Gao's in it.
As MCU states, Mike Colter's words very much sound like a confirmation that we're going to be seeing Wai Ching Ho's heroin trader Madame Gao. Of course, if you saw the events of Iron Fist and Season 2 of Daredevil, you could've guessed the head of the NYC chapter of The Hand was going to be making an appearance. If Colter had watched The Defenders trailer perhaps one more time just before answering, he would've noticed that the only villains we see, other than faceless thugs, are whoever Sigourney Weaver's Alexandra really is, and then possibly Elektra. Gao's confirmation would seem to imply The Defenders miniseries will be a heavy HANDed adventure, but what does her return really mean?
Spoilers if you're one of those who stopped watching Iron Fist before the finale, as the ending saw Gao listening in on a conversation between Joy Meachum and Danny Rand's K'un-Lun friend Davos, who offered to find Rand and kill him. Madame Gao was previously detained by another member of The Hand named Bakuto, who was looking to take Gao's place, at least until he met his presumed end by Davos. Bakuto was thought to be dead, but with The Hand quickly recovering his body, we can't tell for sure. In either case, Gao's appearance in The Defenders has to make you wonder if she'll have Davos and Joy Meachum in tow, perhaps with a bewitched Bakuto tracking her down.
If nothing else, Mike Colter confirmation of Madame Gao's presence would appear to indicate she plays a sizable role in the miniseries. At least, sizable enough for Colter to think she should have been in the trailer. Colter mentioned not long ago that the entire Defenders ensemble would be taking on one enemy who was behind each hero's other conflicts, and while many of us assumed that would be Sigourney Weaver's Alexandra, Gao showed us during Iron Fist that she's down with the dark magic. Who knows what those old bones could do if she were given some more power?