When It's Time to Change, You Got to Rearrange

With Marvel's recent announcement that Thor would become a woman, and that the next Captain America would be black, people are asking "Why?" Someone actually said to me "Why are they turning Captain America black?" There are actually two different hallmarks of the Superhero sub-genre at work here, literal character metamorphosis and a hero's legacy being taken up by another.

While Thor hasn't gone through as many transformations as, say, Spiderman or Jean Grey, there have been a few. The strangest case would have to be the time in the 80's that the mighty Thor was turned into a frog by his spiteful brother, Loki.  He encountered an army of frogs in Central Park (had to look it up, but that's what you call a group of frogs). These frogs were at war with a group of rats, whom Thor helped to defeat. His froggy state only lasted two issues, but one frog that Thor befriended, named Puddlegulp, was later given a shard of Mjolnir, Thor's hammer, which morphed into little froggy-sized hammer. As "Throg" Puddlegulp wields the powers of the thunder god, and is a founding member of the Pet-Avengers.

Frog Thor 

Loki as a woman

And a sex-change isn't completely out of the blue for gods of Asgaard. As the result of a Ragnarok event, all of the Asgaardians were dead, except for Thor who was in a coma.  When they returned, as gods sometimes do, Loki was resurrected as a female. She continued as the goddess of mischief until she sacrificed herself to aid the Avengers and a completely shocked Thor. He then returned as a young boy, with no memory of his past lives.

To really understand this gender-bend, remember how was Thor originally. Classic Thor had a human form, Dr. Donald Blake.  When he tapped his cane he transformed into Thor, and his cane became Mjolnir. Marvel abandoned, this at some point, by having Odin give this power to Thor's ally Beta Ray Bill. Since then, Thor was Thor, but Marvel will be returning to a similar set up. Instead of Donald Blake, Thor's newest host is a woman. They'll have to change a pronoun on Mjolnir's inscription, though.

UPDATE: Finally, eight issues into the new series, Thor's identity is revealed. It wasn't' Lady Sif, Valkyrie or Odin's wife, Frigga as many speculated. It turns out, it was Jane Foster all this time. While its great they're using a character familiar to fans of the films, Dr. Foster is fitting in another sense. In the comics she's been battling cancer. Like the way Donald Blake's limp went away when he was Thor, When Foster wields Mjolnir, the symptoms of her disease and leukemia treatments disappear.

The coming change in Captain America is much simpler and down to earth (as it should be for Cap stories). This is just another person taking up the shield and stripes, which is also not a first in the character's history. There have actually been as many as eighteen others to serve as Captain America in the mainstream Marvel continuity depending on who actually counts.  According to the Marvel Wikia, even the Punisher and Deadpool have had a turn, which is news to me, so I'll just stick to Cap's successors that I'm most aware of.

In the 70's, Steve Rogers became disillusioned with the U.S. government after a cover-up to protect a high-ranking official, whom Rogers exposed as the leader of an organization called the Secret Empire. He went on as Nomad, and the Captain America identity was fought over by two men: Bob Russo and "Scar" Turpin.

Despite their efforts, Rogers awarded his shield to a third man, Roscoe Simons. After proving his fighting skills to Rogers, he underwent training by long-time Captain America ally, Sam Wilson, the Falcon. After Red Skull found out that someone had replaced Rogers, he made a gruesome example of him, crucifying him on a downtown building.

Introducing Steve Rogers as Nomad

Nomad and Falcon find Roscoe's body

In the late 80's, there was a story-line in which Red Skull had managed to discredit Steve Rogers and he was forced to abandon the Captain America identity.  This paved the way for a man named John Walker to take his place. Walker was a former soldier and former "UCWF" wrestler. Much like the "Super-Soldier" serum that gave Rogers his powers, Walker went through the "Power Broker" process to become a vigilante called Super-Patriot before filling the Cap role. He was always a bit harsher than Rogers, but he fought the good fight and even continued after the original Captain America returned, calling himself just Captain before settling on the code-name, U.S.Agent, as a reserve Avenger.

The rogue-ish U.S.Agent clashes with Cap

More recently, after the event's of Marvel's "Civil War" story-line, a more familiar character took up Cap's legacy. Marvel's heroes were at odds over a initiative called the "Superhuman Registration Act." The law was designed to protect civilians, after a disaster triggered by a super-team, who botched a raid on a villain hideout for a reality t.v. show. There were many civilian casualties, and being such a public debacle, Tony Stark decided that the superhero community needed be more responsible, so he was the law's most vocal supporter, and Captain America lead the opposing rebels. It makes sense that the Sentinel of Liberty would fight for the freedom to masked heroes to protect their identities. The debate escalated to a fight, which escalated to a battle between heroes. After this continued far too long, Captain America questioned whether the ideals he fought for were worth so much destruction. He took the only course he could see would stop the fighting; he surrendered himself. On the day of his trial, on the steps to the courthouse, he was shot by an assassin, Crossbones, who was of course hired by Red Skull. James "Bucky" Barnes, Cap's original sidekick, though he was unable to face his mentor after his actions as the Winter Soldier, recovered the shield from Black Widow and wore a suit designed by Tony Stark to become the new Captain America.
Some fans' reactions to the gun-wielding Bucky-Cap were echoed by Clint Barton and Sam Wilson who initially thought Barnes unworthy of the mantle. But he carried on Rogers' legacy, fighting terrorists and aiding the New Avengers to combat the Secret Invasion by the shape-shifting aliens the Skrulls.

Classic Cap and Bucky

Bucky Cap or Captain Buck?

As it turned out, Steve Rogers wasn't really dead. Agent Sharon Carter of S.H.I.E.L.D., under the guise of being controlled by the enemy was able to plant a time displacing device in order to freeze Rogers in time. While Bucky continued his  run as Cap, Rogers worked with the Secret Avengers before fully returning as the Captain we're all familiar with.

Throughout the last few years he greatly expanded the Avengers, went to war in space and defeated a near-impossible threat and returned to Earth to defend it against Thanos and his death-obsessed Black Order. But Marvel is switching it up again, so Steve Rogers is going to lose his strength and vitality. As he's for the first time showing his age, Rogers passes the shield to his longtime ally, Sam Wilson. Too bad Nintendo already has a character named Captain Falcon.

Falcon's first appearance 

Lastly, I couldn't resist bringing up the strangest chapter in Captain America's long history. In the early 90's, Cap battled some werewolves and got infected, so naturally, he became Cap-Wolf!