The CW's "Arrow" Season 3 spoilers hint of an epic action in the next new episode, as Stephen Amell's Oliver Queen fights the head of the League of Assassins, Ra's al Ghul. The promo video shows The Arrow and the villain atop a mountain, each one seemingly ready to kill the other. Meanwhile, fans are treated to some teasers about Oliver's child and the Canary's killer.

Spoiler alert: This Arrow Season 3 update contains spoilers. Read at your own risk.

Matt Nable will be seen in Arrow Season 3, Episode 9 as Ra's al Ghul. This is the second time he is appearing on the show, the first one being Arrow 3x4, "The Magician." The League's patriarch is launching an assault on Starling City in connection to the murder of Sara Lance, aka the Canary.

In an interview with ET Online, Emily Bett Rickards, who plays Felicity Smoak, said Team Arrow will find something that is "almost sort of a bread crumb" in their investigation into Sara's murder. She added this clue is "a gold bread crumb." Viewers might find this "crumb" in Arrow Season 3, Episode 9.

Ra's al Ghul is listed by many Arrow fans as one of the suspects in Sara's death. John Barrowman's Malcolm Merlyn, who is also seen in the Arrow 3x9 promo video, is another suspect. Slade Wilson, aka Deathstroke, is also a suspect. (Spoiler reports have earlier revealed that Manu Bennett is reprising his role as Deathstroke in 2015.)

Meanwhile, the mother of Oliver's child is seen for the second time in "Flash vs. Arrow," the eighth episode of The CW's "The Flash." In this crossover special, Ollie bumps into Sandra (Anna Hopkins), and tells Felicity she is "someone that [he] used to know." Arrow Season 3 is expected to dish more about Oliver's child.

In an interview with The Hollywood Reporter, Arrow showrunner Andrew Kreisberg said that the plot on Oliver Queen's child could be explored further in Arrow Season 3. This interview was published after the airing of Arrow Season 2, Episode 20 ("Seeing Red").

In Arrow 2x20, it is revealed that Moira Queen paid a million dollars so that Ollie's pregnant girlfriend would leave Starling City and never tell Ollie about his unborn child.

"There are certain things on the show that we're comfortable waiting for their right point," Arrow showrunner Marc Guggenheim recently told ET Online, responding to a question about Ollie's ex. In DC Comics, Oliver's child with his college sweetheart Sandra is named Connor Hawke aka Red Arrow.

In "Flash vs. Arrow," the TV version's still unnamed ex calls her child on the phone, but does not mention his name.

Arrow's crossover shows with "The Flash" are over, at least for 2014. The DC Comics adaptation is airing its winter finale (Arrow Season 3, Episode 9) on Dec. 10. This new special episode is called "The Climb."