Some of this page is derived from the Friendship is Magic Wiki.The original article is at Thorax.
Thorax is a male changeling and supporting character who appears briefly at the end of the season six episode The Crystalling - Part 2 before making his prominent debut in The Times They Are A Changeling. In the season six finale, he becomes the new leader of the changelings following the defeat of Queen Chrysalis.
Depiction in the series
Thorax explains to Spike that, he is 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.
Later on in the series, 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 another episode, Thorax teams up with Starlight Glimmer, Trixie, and Discord to save Equestria from changeling invasion. Here, his wings have become coated in crystal glitter. 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 follows Starlight's advice and shares it with her willingly, causing a blast of magic that metamorphoses him into a new colorful form. After Chrysalis is defeated and chased off, Thorax becomes the new leader of the changeling hive.