Mystogan is a former S-Class mage of the Fairy Tail guild and the current king of Edolas. His real name is Jellal, and he is the Edolas counterpart of Jellal Fernandes. He was born as the prince of Edolas, the son of King Faust. As a child, he was seriously injured and was saved by the Exceed Panther Lily, who was exiled from Extalia for helping a human. Growing dissatisfied with his father's use of the interdimensional spell Anima to steal magic power from Earth Land, Mystogan left Edolas and traveled to Earth Land under the name Mystogan. His primary goal was to close the Anima portals and end his father's destructive campaign. During his travels, he encountered and briefly cared for the young Wendy Marvell before placing her under the care of an old man named Roubaul. He eventually joined the Fairy Tail guild and became one of its most powerful and mysterious members.

Mystogan possesses a reserved and reclusive personality. He dislikes social interaction and goes to great lengths to keep his face hidden from others. Whenever he visits the guild hall to take a job, he casts a powerful sleep spell that puts all the other members to sleep, leaving only Master Makarov and Laxus able to resist its effects. He wears a mask and a bandana covering most of his face, and he avoids being seen because his appearance is identical to Jellal Fernandes, the man who caused Erza Scarlet great pain. He genuinely wishes to spare Erza that suffering. Despite his shyness and introversion, Mystogan is deeply loyal to Fairy Tail and its members. He is willing to act alone and in secret to protect the guild, as shown during the war with Phantom Lord, where he single-handedly defeated all of Phantom Lord's subdivisions and restored Makarov's depleted magic power without anyone knowing. He demonstrates a strong sense of responsibility and maturity, often placing the needs of others above his own.

Mystogan's role in the story begins as an enigmatic background figure whose true identity is gradually revealed. He becomes a central figure during the Battle of Fairy Tail arc, when he confronts Laxus during his attempted takeover of the guild. In the midst of their fight, Laxus's lightning burns off Mystogan's mask, exposing his face to Natsu and Erza. Erza is stunned to see a face identical to Jellal's, but Mystogan insists he is not the Jellal she knew and teleports away. Later, during the Edolas arc, Mystogan's full background is uncovered. He returns to Edolas, reveals himself as the rightful prince, and opposes his father's regime. With help from Fairy Tail, he shuts down the Anima, freeing the magic power stolen from Earth Land. In the end, he decides to remain in Edolas as its new king, vowing to lead his people into a future without reliance on magic. He bids farewell to his guildmates and takes Panther Lily with him, wishing for his friend's happiness.

Key relationships define Mystogan's journey. His closest bond is with Panther Lily, the Exceed who saved his life and later becomes his loyal companion and advisor. With Makarov, Mystogan shares a mentor-like dynamic; Makarov is one of the few people who can remain awake in Mystogan's presence and who trusts him implicitly. His relationship with Erza is complicated by his resemblance to her traumatic past, and he carefully avoids her to prevent reopening old wounds. Laxus acts as a rival who knows more about Mystogan than most, and their confrontation forces Mystogan to reveal his face. He also shares a brief but meaningful connection with Wendy, having once protected her as a child, and he is surprised and pleased to see her later thriving in Fairy Tail.

In terms of development, Mystogan transforms from a shadowy, self-isolating figure into a decisive leader who accepts his responsibility for Edolas. He evolves from hiding his identity out of fear of causing pain to openly standing before an entire kingdom as their king. His personal arc emphasizes themes of duty, sacrifice, and the importance of protecting others even at great personal cost.

Mystogan's magical abilities center on sleep-inducing magic and illusion magic, which he channels through multiple magical staffs. His signature technique is Mist Body, a spell that puts everyone in his vicinity to sleep; even Master Makarov is only barely able to resist it. He can also transform his body into mist, allowing him to evade physical and magical attacks. Using his staffs, he can create powerful barriers and attack spells. Triple Magic Circle: Mirror Water reflects enemy spells back at them using three overlapping magic circles. Quintuple Magic Circle: Sacred Song (or Kagura) seals an opponent within a pillar of light that ultimately puts them to sleep with a concentrated beam of magical energy. His most devastating known technique is Septuple Magic Circle: Void, which traps an opponent in an area of seven overlapping circles and completely erases them. Mystogan also uses illusion magic to disorient enemies, such as Tower of Babel, which creates a mental attack to break down an opponent's mind. His abilities make him one of the most formidable mages in Fairy Tail, capable of handling entire armies alone.