Loki (Marvel)

Loki is maybe Marvel's most iconic villain. None comic readers may this of Loki as a cis but as far back as Norse        mythology Loki has always been a gender fluid character. Loki begins a redemption arc in the comic Journey into Mystery that moves into the Young Avengers series written by Kieron Gillen and drawn by Jamie McKelvie with colors by Matt Wilson. The series then lead into Loki Agent of Asgard where series writer Al Ewing had said that Loki is bisexual and that he intended to explore that. While this didn't seem to be explored in the final results we saw we did see Al Ewing and the rest of the creative team exploring Loki's gender to degrees. In Agent of Asgard Loki states that they can only become themselves hence being able to take a female form. Also during this same run Odin calls Loki "My Child who is neither my Son nor my Daughter" since Loki is genderfluid.

Spoilers for Last Days of Loki

After Loki's death they are revived this time as the goddess of stories. Loki constantly switches between genders and the people reacting to them use the pronoun of whatever Loki displays to address him. We also see once again Loki explaining to a character that they feel themselves beyond the binary during these events.

State of the Character
Sadly the only version we have in current publication of Loki is "evil". The editors at Marvel seem to have a misunderstanding of Loki's gender when asked about them at a convention they replied "Will the Loki be Guy Loki or Girl Loki we can't say." The run has also displayed the classic female Loki who had taken over the Lady Sif's body taunting the "male" Loki's addressing them as such while in battle with Thor. So do not read Mighty Thor if you are looking for more Genderfluid representation.

Recommended Reading
If you want to get Loki at their very best then these are the titles to look out for.

Young Avengers volume 2

Loki Agent of Asgard volume 1

Loki Agent of Asgard volume 3

Unbeatable Squirrel Girl 7 and 8 (Volume 1)