The second season of "Marvel's Agents of S.H.I.E.L.D." is quite different than the first. Its tone is more serious as characters are learning more about themselves and how they work together as a team.

In Tuesday's episode, titled "Who You Really Are," a familiar character returned. First seen in the first Thor film, Lady Sif (played by Jaimie Alexander) has once again joined up with the agents. According to Comic Book, the fierce Asgardian female warrior has lost her memory after she fights a "mysterious warrior." Her true mission will supposedly send "shockwaves" through the agency.

Lady Sif guest starred in the show in its first season. However, it looks like this time her appearance has been more enjoyable to viewers as her role offers the team's insight about Skye's transformation as an Inhuman and has given more impact on the team's storyline, says The Latino Post.

"Marvel's Agents of S.H.I.E.L.D." has made its way to be an integral part of the Marvel Cinematic Universe as more characters and stories from the films and comics have made their way to the small screen. Inhumans, which the show is currently studying, will be a part of the film franchise in the next couple of years and references to The Avengers, Thor: The Dark World and Captain America: The Winter Soldier have also been mentioned in past episodes.

The series stars Clark Gregg As Director Phil Coulson, Ming-Na Wen as Agent Melinda May, Brett Dalton as Grant War, Chloe Bennet as Agent Skye, lain De Caestecker as Agent Leo Fitz, Elizabeth Henstridge as Agent Jemma Simmons and Nick Blood as Lance Hunter.