The fifth instalment of Phase 3 of the Marvel Cinematic Universe, Thor: Ragnarok is set to take us back to Asgard as Thor (Chris Hemsworth) faces the Norse apocalypse. I loved the first Thor, so this is one of the more eagerly anticipated Phase 3 films for me - especially as Kevin Feige has confirmed that it will be instrumental in setting up the events of [The Avengers: Infinity War](tag:738027):
"This is a very important movie for us in Phase 3. We plan on taking Thor to another level. It picks up where we leave Thor in Avengers: Age of Ultron and impacts everything that comes after."
We already know that Thor won't appear in [Captain America: Civil War](tag:994409) which releases next year, this is because Thor: Ragnarok will pick up Thor's narrative immediately after the events of [The Avengers: Age Of Ultron](tag:293035) which sees him return to Asgard in search of clarification of the meaning of the vision he experienced - in which he stumbles through an Asgardian party and encounters a blind, cryptic Heimdall, and from which was cut a scene where he is confronted by Loki (Tom Hiddleston).
In the comics Thor doesn't take part in the civil war because of the events of Ragnarok (as he's currently in a limbo-like death state following Ragnarok) so there's a continuity connection there at least.
What is Ragnarok?
Ragnarok is the Norse apocalypse which occurs in a constantly repeating cycle of the death and rebirth of Asgard and it's people. It's happened a few times in the comics, the most recent and important occurrence was that which was brought about by Loki and the fire demon Sutfur.
There's a lot of players in this iteration of Ragnarok, including a number of Norse gods who haven't been introduced yet. With the death of Frigga (Rene Russo) and Loki presumed dead, it might be time to introduce some of these gods in [Thor: Ragnarok](tag:956858) particularly the ones who appeared in the comics.
In the Marvel canon Týr is the God of War - another child of Odin and Frigga, an older half-brother to Thor (he's a half-brother as canonically Thor is birthed by the goddess Gaea, not Frigga).
Týr only has one hand, as his left hand was bitten off by Fenris - the Wolf God. Whilst he's generally stood by as a protector of Asgard, like Loki he has also rebelled against his father as a reaction to Thor's perceived superiority. He's battled Surtur (the fire demon mentioned above who's instrumental to the events of Ragnarok) to defend Asgard, and also fought off Norman Osborn (Green Goblin) when he launched an attack on the rebuilt Asgard, defying a prophecy that predicted his death during this battle.
He has actually been introduced in the MCU, not as the son of Odin but as the Commander of the Einherjar - the Asgardian Army in [Thor: The Dark World](tag:206462). He was portrayed by Clive Russell. However he only had a very minor part in this film, barely a few lines spoken. You may not even remember him, and he still had two arms here... It's entirely possible that Týr could make an appearance to defend against Ragnarok, with a bigger part and maybe even some character development this time, though perhaps at the cost of an arm.
Fenris is one of Loki's many offspring, a child born from the shape-shifting sorceress Angerboda. He appears as a huge wolf (at least 15-feet tall), he's incredibly strong and intelligent and he can change his shape to appear as a God or become the size of a regular wolf.
As he was deemed too dangerous to be allowed to roam free but was too strong to keep contained, Odin commanded enchanted bonds (Gleipnir) be created to bind him. The gods tricked Fenris into trying to break the binding, trapping him and Týr had his arm bitten off as a result of their trickery. They bound the wolf to a rock, but it was prophesied that Fenris would eat Odin when Ragnarok came.
During the final Ragnarok Loki unchained Fenris from the rock to attack Asgard, and he took part in the shattering of Mjolnir - Thor's hammer. He was eventually defeated by Beta Ray Bill, but he returned to life and swallowed the sun and moon - heralding the destruction of Asgard.
Though it's unlikely that the wolf would appear as a child of Loki (unless he'd gotten busy on his sneaky trips out of Asgard) he does provide a notable antagonistic force during Ragnarok and, let's be honest, it would be cool to see Thor fight a really big wolf.
Another of Loki's beastly offspring, Jörmungand is also known as the Midgard Serpent, because funnily enough he's a frigging huge snake.
Like Fenris, Jörmungand was banished from Asgard for being too dangerous, sent to Midgard (Earth) into the depths of the oceans where he grew massive - long enough to circle the entire Earth with his body. By doing this he can cause storms, earthquakes, floods and landslides and can also bridge the gap between Earth and Asgard with his body because why the hell not?
He and Thor have fought many times due to a prophecy that they would both perish at each other's hands during Ragnarok.
Jörmungand appears during a few Ragnaroks, once killing a fake-Thor as part of an attempt to subvert the prophecy. He is eventually killed by Thor but escapes from Hel and swallows Thor whole (don't worry - he got out). The Serpent was later resurrected by Morgan le Fay, and reappears as an omen of doom during the final Ragnarok.
Again, unlikely to appear as a child of Loki, but Jörmungand plays a big part in the Marvel-Norse mythology and, again, it would make for some pretty interesting stuff seeing Thor go head-to-head with a giant snake.