"DC's Legends of Tomorrow" has begun to assemble its Justice Society of America.

Entertainment Weekly reports that "iZombie" alum Matthew MacCaull has been cast as Henry Heywood Sr., better known as Commander Steel, in the upcoming second season of the CW series.

Although we've known since the Season 1 finale, with the introduction of Patrick J. Adams as Hourman, that the Justice Society would debut in Season 2, it wasn't until Comic-Con International that we learned some of the other heroes that will fill the team's ranks: Obsidian, Stargirl and Doctor Mid-Nite, Vixen (played by Maisie Richardson-Sellers) and Steel.

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According to EW, Commander Steel is the grandfather of Dr. Nate Heywood, aka Citizen Steel, the role Nick Zano was cast to play in June.

MacCaull's credits also include "Fringe," "Tomorrowland" and "Star Trek Beyond."

"DC's Legends of Tomorrow" returns Oct. 13 on The CW.