'Legends of Tomorrow' season 2 spoilers, updates: JSA to go up against Legion of Doom? Obsidian cast, John Constantine to make a cameo?

The Justice Society of America (JSA) might go up against the Legion of Doom when "Legends of Tomorrow" returns to the small screens with season 2 this October.

When the maiden season of "Legends of Tomorrow" ended, Hourman/Rex Tyler (Patrick J. Adam) of the JSA appeared to warn the Waveriders of what could happen should they continue with their plans. What Hourman said seemed to imply that the JSA and time travel will be vital parts of the Waveriders' plans for the second season.

Nevertheless, there are talks that the Legion of Doom, composed of Reverse Flash (Matt Letscher), Captain Cold (Wentworth Miller), Malcolm Merlyn (John Barrowman), and Damien Darhk (Neal McDonough), will be going up against the JSA and the Legends team.

Six past and modern era team members will comprise the JSA: Hourman, Stargirl (Sarah Gray), Commander Steel (Matthew MacCaull), Citizen Steel (Nick Zano), Dr. Mid-Nite (yet to be cast), Vixen (Maisie Richardson-Sellers), and Obsidian.

The International Business Times has reported that Lance Henriksen has been cast as Obsidian. The 76-year-old genre actor — best known for his role as Bishop in the "Alien" franchise — will make his first appearance in episode 5 of "Legends of Tomorrow" season 2.

In comic book lore, Obsidian is Green Lantern's son. He is able to fuse with his own shadow — which is why he could fly and pass through solid objects — as well as possess other people's shadows. The character is supposed to be one of the younger members of the JSA.

With an older actor being cast for the role, Comicbook.com noted that the Waveriders could meet Obsidian in the present-day or in the future.

Meanwhile, "Legends of Tomorrow" executive producer Phil Klemmer subtly hinted that John Constantine (Matt Ryan) could make a cameo appearance on the show. The character has made cameo appearances in "Arrow" before.

After "Constantine" was apparently canceled, fans longed to see the character back on "Arrow." However, since this doesn't seem to be happening in the said series' fifth season, it looks like fans' clamor will be allayed by an appearance in "Legends of Tomorrow."

"If this show goes as many seasons as I hope it does, it will be a crime for him not to appear in our universe," Klemmer told Zap2it.

"Legends of Tomorrow" season 2 will debut on Thursday, Oct. 13, at 8 p.m. EDT on The CW.