As described in Warcraft 3, Malfurion is the twin brother to Illidan Stormrage. Tyrande Whisperwind was a constant childhood companion to him, and has since become his lover. Malfurion is over 10,000 years old, as indicated by his involvement in both the first war against the Burning Legion and in the events of Warcraft 3.
Warcraft 3 depicts the demigod Cenarius teaching Malfurion the ways of druidism, a practice which, according to the lore of Azeroth (Blizzard’s Warcraft world) was nearly unheard of in the time of the First Invasion. While there had been other students to the demigod, Malfurion was the first to be taught and still retain his original form. All others had changed to become forest spirits similar to Cenarius himself. Malfurion proved to be extraordinarily adept in the use of this new power, possibly due to his already benevolent nature, and quickly became a force to reckon with.
In sharp contrast to his brother, Malfurion displays a temperate disposition throughout the Warcraft games and literature. He consistently places the needs and welfare of others above his own and does not seek out power simply for its own sake. Even when roused to anger, he remains compassionate, especially in matters concerning those he cares for.
Malfurion Stormrage fought in the First Invasion of the Burning Legion and was instrumental in the eventual victory of the forces of Azeroth. He was responsible for the death of Lord Xavius (both as a Night Elf and then again when Xavius had been transformed into a satyr). With the help of his brother, Malfurion used the power of the Demon Soul to close the portal created within the Well of Eternity. This action prevented the Dark Titan, Sargeras, from entering into Azeroth. The energies released by this act inadvertently caused the Well’s collapse. This, in turn, sank the ancient Night Elven capital Zin-Azshari to the bottom of the sea and split the continent of Kalimdor into two separate landmasses. When his brother, Illidan Stormrage, recreated the Well in a new location atop Mount Hyjal, he was discovered by a group of Night Elves surveying the summit. Illidan slew several of them before being detained and brought to trial. The ultimate judgement for his crimes was left to Malfurion, who spared Illidan a death sentence, instead having him imprisoned indefinitely. Maiev Shadowsong was assigned to be Illidan’s jailor.
Sometime between then and the Second Invasion of the Burning Legion, Malfurion, now an Archdruid, entered the Emerald Dream along with several other druids, until he was awakened by Tyrande Whisperwind. He fought against the Burning Legion a second time and he performed the ritual that destroyed Archimonde and damaged the World Tree at the Battle of Mount Hyjal, thus severing the Night Elves’ connection to it and taking away their immortality.
After the battle, Malfurion worked to restore Kalimdor to its original greatness but after receiving a message from Maiev he left for Lordaeron to face his brother Illidan, whom the Warden had been tracking. Once there, Malfurion sought to stop Illidan’s plans by destroying the Eye of Sargeras. However upon learning that his love, Tyrande, was in danger, Illidan agreed to help Malfurion save her. After Tyrande had been saved Malfurion spared Illidan’s life and Illidan chose to run to Outland to escape the demon lord Kil’jaeden (Kil’jaeden had tasked Illidan with destroying the Frozen Throne in which the Lich King resided, but Illidan was unsuccessful and thus wanted to flee so he could save himself from the demon’s wrath).