The most powerful, feared and evil mage in the wizard world who has the ability to kill any living thing around him. He is known to have unimaginable power which has been used to create living demons such as Lullaby and Deliora.
Little is known about Zeref and his origins. Most have known him to be an incredibly powerful mage from ancient times who wielded and mastered dark magic, created tens of thousands of demons and threw the world into chaos. He has even been considered, by some, to have been one of the most powerful mages of the wizard world, especially by the strongest wizards, the Wizard Saints. The fact that the very mention of his name brings shivers to many mages is proof of his dark legacy. But despite the belief that Zeref was killed, Ultear revealed that, till this very day, he is still alive but was trapped in a prison that sealed his inner darkness. Although the Grimoire Heart Guild, to which Ultear is a member of, has been searching for the keys to awaken Zeref from his slumber and free him from this prison, he reveals that he has already been awoken and that he was never asleep to begin with, adding that the so-called keys were created by myths throughout the history of time. He also seems to know Natsu personally after stating his name and claims that he is the only one who can stop him for reasons yet to be revealed. Zeref's whereabouts following the seven year time skip are currently unknown.
Zeref is first shown on Tenrou Island where he tries to remain isolated from the world. After a pack of wolves approached him and were killed by his uncontrolled magic, he apologizes and falls into a state of despair. He later encounters Elfman and Evergreen whom he warns to stay away from him. But as soon as his dark magic begins to activate involuntarily, Natsu arrives just in time to save the duo. Zeref, who is so happy to see Natsu that he is near tears, gets punched by the named saviour, claiming no knowledge of who Zeref is, let alone his name. Once he becomes disappointed that Natsu is still not strong enough to kill him, his uncontrollable magic is released again, which is stopped by Natsu's scarf. Zeref then escapes and continues to sob from Natsu's current inability to put an end to his misery. However, the wave of Zeref's power managed to reach the Grimoire Heart Guild, giving away his location.
Once the Grimoire Heart Guild reached Tenrou Island, Ultear immediately went in search of Zeref while her fellow members faced off against the members of Fairy Tail. Once the fighting between the two guilds ensued, Zeref sensed impending danger and predicted the possibility of another war which indicates that he may have been involved in a previous war at some point. He then found and approached Ultear from behind with an extremely angered face after he realized that she and her guild were the root cause of the conflict. He immediately tells her that he has no intention of getting involved in any war and demands that she and her guild leave the island. Although his statement and his evil glare shocked and frightened Ultear, she managed to defeat him with ease because of his weakened power in his "slumbering state". She then yells out that she finally had him, adding that he will awaken to bring about the ultimate world of magic.
While unconscious, Zeref is dragged around by Ultear and later Meredy who is chased by Juvia on Gray's order to stop her and retrieve him. However, they run into Zancrow who knocks back the two girls in an attempt to take Zeref back to Hades himself. But at that point, Zeref regains consciousness and casts a spell on him, presumably killing him in the process. After regaining his composure, Zeref apologizes to Zancrow and expresses his relief that Juvia and Meredy remained unharmed by his spontaneous attack. He then walks away and remarks that he has no reason to come to this age for he is neither an enemy nor a friend of anyone. However, if an age is about to end, he says that he may awaken and wishes that Natsu stops him before that happens.
Later he emerges from the shadows in the Grimoire Heart airship following its war against Fairy Tail, and tells the remaining members of the Kin of Purgatory and Hades that he will bring forth the end of the world. After looking at him in disbelief, Hades orders Kain and Rustyrose to hand him the key but Zeref informs him that its not necessary for he is already awake. Confused, Zeref explains that the keys to his resurrection was nothing more than a myth created by a cult that worshiped the Black Mage. But Hades exclaims that it can't be possible since he saw Ultear defeat him using his "eye". To clarify things, Zeref tells him that when he learned the value of human life after watching countless humans die in a war 400 years ago, he realized that the more he understands its value, the more his body randomly steals souls and when he completely forgets about it, he is able to fully control his powers. He then tells them that their evil ambitions have triggered his powers and summoned Acnologia, claiming that it would end the current era. As he lists their sins, he casts a spell that severely damages the airship and instantly kills Hades who falls to the ground. However, he senses something in the sky and presumes that Acnologia has come.
After the explosion of the whole Tenrou Island, he says to Natsu that it is over once and for all by shutting his eyes.
Zeref, known to be the most powerful dark mage, was widely known for his dark magic. Although recent chapters have shown that he is unable to control his magic due to its immense power, it is unknown whether he was able to do so before. However, it has been revealed that he has both the ability to bring about death as well as create life, particularly those of demons. In recent appearances, Zeref has been shown to use a spell which instantly kills all lifeforms within a certain radius. However, he has little control over when this magic activates, and is reluctant to use it for fear of killing others.
One of his confirmed magic is the ability to take the life of any living thing around him which Zeref named "The Death Preying." This was shown after all the plants and animals, such as birds and trees, withered and perished after he released his magic. It seems that his powers activate at random times, but Zeref is able to determine when they are about to occur which gives a person enough time to escape. It seems that so far, only Natsu's scarf is able to stop his magic. Whether or not there are other objects or magic able to nullify his dark powers is currently unknown.
Zeref also is known for casting living magic, an ancient form of magic that brings things to life under the master's control. Many of his creations have minds of their own and most are giant demons such as Lullaby (a flute that can transform into a giant demon who can bring death to those who hears its song) and Deliora (a giant demon who destroyed countless cities in the North and was frozen in a block of ice created by Ur, Gray's teacher).