Thorax

Thorax is a male changeling and supporting character who appears in the season six episodes The Times They Are A Changeling, To Where and Back Again - Part 1, and To Where and Back Again - Part 2. In the season six finale, he becomes the new leader of the changelings.

Design and development
In contrast to other changelings such as Kevin, Thorax has somewhat wholer ears and tail, rounder and slightly differently-colored eyes, and differently-colored back armor.

In entomology, the term "thorax" refers to the midsection of an insect's body.

Depiction in the series
In The Times They Are A Changeling, Thorax first appears pretending to be Spike's mirror reflection, but he is exposed when he does not copy Spike's exact movements. Spike is scared of Thorax at first, but he starts to warm up to him after Thorax saves him from falling into a deep crevice. Thorax explains that, unlike the other changelings, he wants to make friends, having desired so ever since he saw the Mane Six fight off the evil changelings during the royal wedding in Canterlot.

Thorax also explains that he was drawn to the Crystal Empire due to the love the Crystal Ponies had during Flurry Heart's Crystalling, but he has been unable to sustain himself off of that love because of what he is. Spike, sympathetic to Thorax's dilemma, decides to help him.

After Spike fails to convince the ponies of the idea that a changeling can be nice, he has Thorax disguise himself as a Crystal Pony—proportioned similarly to Plaid Stripes, "Pearly Whites", filly Fluttershy, and later filly Applejack—named Crystal Hoof. With this disguise, Thorax is able to meet Princess Twilight Sparkle and mingle with the Empire populace. However, his cover is blown when he meets Flurry Heart and the love around her causes him to succumb to his basic instincts. In the confrontation that ensues, Spike briefly hesitates to stand up for Thorax, and Thorax runs off in tears, feeling betrayed.

When Spike returns to Thorax's cave and attempts to make amends, Thorax angrily turns him away at first, but he demonstrates his friendship by saving Spike from the crevice a second time. Spike brings Thorax before the ponies again and expresses through song that Thorax is good and that even changelings deserve a chance at friendship. Twilight, moved by Spike's courage and kindness, accepts Thorax as her friend, and the other ponies follow suit, welcoming Thorax as an official citizen of the Crystal Empire.

Thorax gratefully accepts the ponies' offer of friendship and expresses a desire to learn all he can about friendship and share what he learns with his fellow changelings so they can share love with each other instead of stealing it from others.

In To Where and Back Again - Part 1, Thorax teams up with Starlight Glimmer, Trixie, and Discord to save Equestria from changeling invasion, having been sent by Sunburst to find help after Princess Cadance, Shining Armor, and Flurry Heart were kidnapped at the same time as the Mane Six and Royal Sisters. Here, his wings have become coated in crystal glitter. In Part 2, Thorax is forced to confront his doubts about returning to the kingdom where he was born, and he guides his allies into the Changeling Kingdom when the properties of Queen Chrysalis' throne disables their magic.

Near the end of the episode, it is revealed that Thorax's wings changed as a result of him sharing love with the Crystal Ponies. When Chrysalis tries to absorb that love from him, he shares it with her willingly, causing a blast of magic that transforms him into a colorful creature. This leads the other Changelings to follow his lead, resulting in Chrysalis' throne being destroyed and freeing all of the kidnapped ponies. After Chrysalis is defeated and chased off, Thorax becomes the new leader of the changeling hive, whom Princess Celestia is pleased to open up relations with.

Personality
Unlike most changelings, Thorax is portrayed as kind and considerate with a sincere yearning for friendship. However, prior to meeting Spike, he bears a lot of doubt that anyone could ever want to be friends with a changeling. When offered kindness or surrounded by love, Thorax occasionally reverts to his basic impulses and hisses threateningly at others.

Quotes
"The ice is pretty slippery. I wouldn't want you to get hurt because of me."

- The Times They Are A Changeling

"I'm Thorax. I can't believe you want to help me."

- The Times They Are A Changeling

"[hisses] Uh! S-Sorry! Kindness like that kind of brings it out. Do you still wanna be my friend?"

- The Times They Are A Changeling

"I like to brag to all my friends about my letters from Spike the Brave and Glorious."

- The Times They Are A Changeling

"I... [hisses] I'm so... [hisses] ...sorry...! I can't... Can't [hisses] ...stop!"

- The Times They Are A Changeling

"Why do you think I would help you? I'm an 'evil changeling'!"

- The Times They Are A Changeling

"I want to know all about friendship, and maybe one day I can take that knowledge back to the Changeling Kingdom! If my kind learned how to create love for one another, maybe they wouldn't have to take it from others!"

- The Times They Are A Changeling