Lady Sif is of the second generation gods and is the destined wife of Thor.She is one of the strongest asgardian woman, and second in combat only to Valkyrie.

While Sif, Thor and Loki where adolescents Loki cut off her golden hair as a foul prank because of her liking towards Thor, Loki found himself obligated to restore it,but he did so with trickery.Loki had broke a bargain he made with the trolls and stole the golden hair from them.The hair he had replenished for Sif soon turned black because of its unfinished state,it was not treated with a special potion that would preserve it golden color forever.Her parents tired of her crying because of her hair sent her to learn the ways of the warriors,as a shield maiden.

When she came back she found Thor was in a relationship with Jane Foster,from which Odin eagerly wanted Thor to abandon because of Sif's arrival.As Thor saw Sif again his feelings arose to the occasion and was together again with her passionately.When they finally decided to marry Sif found that Thor was very much attached to mortal ways,which she in fact did not have much of an interest for,she tried various times to accustom the mundane life,during which she meets Eric Masterson but could not,so she returned to Asguard and left Thor to his deeds.

They're wedding day is postponed until they can settle their differences.

Lady Sif lost an arm during Thor's confrontation with Fenris and Ulik in the events of Ragnarök.Then,during the second wave of the war she avenges Valkyrie who was slain by Durok the Demolisher,and stabs him with Valkyries own sword Dragonfang .She then died with the rest of Asgard in the third and final wave,which no one survived.

After Thor's rebirth, the rebuilding of Asgrad and the "freeing" of the rest of the Aesir Sif remains trapped in the body of Mrs. Chambers, an old dying woman, due to the actions of Loki.