Question: Who was an enemy of the fictional character worked on by Esad T. Ribic that was the adoptive brother of Thor?
Context: Jane Foster is a fictional character appearing in American comic books published by Marvel Comics, most commonly depicted as a supporting character of the superhero Thor.  Created by writers Stan Lee and Larry Lieber, and artist Jack Kirby, the character first appeared in "Journey into Mystery" #84 (Sept. 1962).  For many years, Foster was a nurse employed by Dr. Donald Blake, Thor's first mortal host, before becoming a doctor herself.  In 2014, Foster was revealed to be deemed worthy to wield Thor's hammer Mjolnir when the former is no longer able, adopting the name of Thor, the "Goddess of Thunder", and joining the Avengers. Seth Ezekiel Cohen is a fictional character on the FOX television series "The O.C.", portrayed by Adam Brody.  Seth is one of the "core four" characters on "The O.C." alongside Ryan Atwood, Marissa Cooper, and Summer Roberts.  Seth's friendship with Ryan, who eventually became his adoptive brother, formed a focal point of the series along with their romances.  Seth married Summer in the series finale.  His other relationships were with Anna Stern and Alex Kelly.  Seth's goal was to attend Brown University, but he ends up going to Rhode Island School of Design (RISD) and continuing work on his comic book "Atomic County".  The role saw Brody win four Teen Choice Awards from five nominations, from 2004 to 2006. Sif is a fictional character appearing in American comic books published by Marvel Comics.  The character is depicted commonly in association with the superhero Thor.  Based on the Norse goddess Sif, she was created by Stan Lee and Jack Kirby and first appeared in "Journey Into Mystery" #102 (March 1964).  As an Asgardian warrior and lover of Thor, Sif often accompanies Thor into battle.  She has also battled alongside Balder, who has developed an unrequited attraction to her, as she never shows affection for anyone but Thor and certain individuals who have proved worthy to wield his hammer, Mjolnir, such as the noble alien warrior Beta Ray Bill and the mortal Eric Masterson.  Sif has appeared in various media adaptations of Thor, including the 2011 Marvel Cinematic Universe film "Thor", its 2013 sequel "", and the television series "Agents of S.H.I.E.L.D.", in which she is portrayed by Jaimie Alexander. Esad T. Ribić (born 10 November 1972) is a Croatian comic book artist, known for his work on various titles for Marvel Comics, including "Loki", "Silver Surfer: Requiem", "Sub-Mariner: The Depths" and the 2015 "Secret Wars". Loki is a fictional character appearing in American comic books published by Marvel Comics.  He is the adoptive brother and often the enemy of Thor.  He is based on the being of the same name from Norse mythology.  The character first appeared historically in "Venus" No. 6 (August 1949) and in modern-day in "Journey into Mystery" No. 85 (October 1962).  The character was created by writer Stan Lee, scripter Larry Lieber, and penciller Jack Kirby.  Though normally portrayed as a supervillain, he is sometimes depicted as an antihero. Christine "Chrissie" White (also Sugden) is a fictional character from the British ITV soap opera, "Emmerdale", played by Louise Marwood.  She made her first screen appearance on 23 October 2014.  The character and casting was announced on 4 October 2014.  The character was the fiance of established character Robert Sugden (Ryan Hawley), who announced the character to return to the series after five years.  Her storylines have included: her turbulent relationship and later marriage to Robert; being caught up in a raid at Home Farm organised by Robert; defending her teenage son Lachlan White (Thomas Atkinson) when it is revealed that he sexually assaulted Alicia Metcalfe (Natalie Anderson); discovering that Robert has been having an affair with Aaron Livesy (Danny Miller); accidentally causing a helicopter crash which killed multiple residents; discovering that Lawrence White (John Bowe) is not her biological father; embarking on a relationship with Robert's adoptive brother Andy Sugden (Kelvin Fletcher); framing Andy for Lawrence's attempted murder when Lachlan shoots him after discovering that Andy had cheated on her; and her intense feud with her younger sister Rebecca White (Emily Head). Jake the Dog is a fictional character and one of the main cast in the American animated television series "Adventure Time" created by Pendleton Ward.  He is voiced by John DiMaggio.  The character made his debut in the original pilot.  Jake is Finn's best friend and adoptive brother.  He is a shape-shifting dog who is in his 30s in "magical dog years".  He was conceived by Joshua and an extra-dimensional creature and as a result, Jake can stretch, shrink, or mold any part of his body to any shape and almost any size, ranging from becoming gigantic to becoming incredibly small.  He acts as a confidant and mentor to his energetic brother, though has a tendency to give somewhat questionable advice.  Jake has a laid-back attitude in most situations, but loves adventure and will eagerly fight when he needs to.  His powers help Finn considerably in combat and transportation, but are also sometimes used as nothing more than jovial forms of expression.  Jake is in a relationship with Lady Rainicorn voiced by Niki Yang; they have five children together as seen in "Jake the Dad".  He met Lady in the pilot episode and is quite skilled at playing the viola, which houses a worm called Shelby. Will Griggs (also Sebastian Barnes) is a fictional character from the Australian Network Ten soap opera "Neighbours", played by Christian Clark.  The character debuted on-screen in the episode airing on 12 October 2006.  He was introduced into the serial as part of a group of four characters branded as "20 somethings".  Clark quit the series prematurely to concentrate on a film career and Will departed on 23 January 2007.  Upon his departure from the serial, his younger adoptive brother Oliver Barnes was written into storylines, the plot revealed that Will had used Oliver's life story and a new name to hide his true identity. James Worthington "J.J." Gordon Jr. is a fictional character, a supervillain in DC Comics and an enemy of Batman.  He is the son of James Gordon and Barbara Eileen Gordon, and the adoptive brother (or biological brother, depending on the continuity) of Barbara Gordon, who later tries to bring him to justice as Batgirl. Andrew "Andy" Sugden (also Hopwood) is a fictional character from the British ITV soap opera, "Emmerdale", played by Kelvin Fletcher.  He made his first on-screen appearance on 4 July 1996.  Andy is the son of Billy (David Crellin) and Trisha Hopwood, and the half-brother of Daz Eden (Luke Tittensor).  However, the character was adopted by Jack (Clive Hornby) and Sarah Sugden (Alyson Spiro), and became the adoptive brother of Robert (Christopher Smith/Karl Davies/Ryan Hawley) and Victoria Sugden (Jessica Haywood/Hannah Midgley/Isabel Hodgins).
Answer: Thor