Evergrowth

The Evergrowth was a collective hivemind created when the Sporemounds of ancient Draenor tapped into the Spirit of Life, which ignited a crude communal sentience that allowed Draenor's plants to act as a single massive organism. If any major threat arose, the Evergrowth could react in unison, yet such threats were non-existent, for the Evergrowth dominated everything in sight, and nothing could hold it at bay. Most of it was initially destroyed by the giant Grond and his descendants, while many years later it was finally destroyed forever when the Apexis used the Breath of Rukhmar to incinerate the armies of the treant Gnarlgar.

Grond and the Sporemounds
When the titan Aggramar came across Draenor in his travels, he was intrigued by the world, but foresaw doom for the planet if the Evergrowth was allowed to grow unchecked, as it would eventually consume everything on the world, including the elemental spirits. Once that happened, the Evergrowth would devour itself, and Draenor would be left a wasteland devoid of life. Aggramar's natural affinity for order compelled him to take action, but he did not wish to completely destroy Draenor's plant life, only to temper it. Thus, he would need to neutralize the Sporemounds, the heart of the Evergrowth's power.

The titan considered destroying the Sporemounds himself, but since his power was so great it risked irreparably damaging or even shattering Draenor and because he could not stand guard over the world forever, he instead decided to create a mighty servant in his own image to uproot the Sporemounds. Using a massive elemental storm, Aggramar caused a mountain to groan to life and named it Grond. The giant began marching across the world to conquer the Evergrowth until he reached the nearest Sporemound, at which point he defeated and tore it from the world's surface with ease. The other Sporemounds shivered in agony at the destruction of their kin. Mere roots would not topple Grond; instead, the Sporemounds would need to adapt.

Each Sporemound drained the surrounding wilds of life essence, leaving behind only withered tracts of land. Infused with these energies, the Sporemounds arose to walk the world. There were three, each embodying a different region of the Evergrowth: Zang, whose hide was covered in swamps and mushroom thickets; Botaan, who was covered with primal forestlands; and Naanu, who wore a fleece of dense jungles. As one the Sporemounds moved against Grond, and Draenor buckled under the weight of the warring giants. Aggramar watched the battle from the skies over Draenor. Zang, Botaan and Naanu were determined to protect the Evergrowth at any cost, and through their communal sentience they moved in perfect unison against Grond, nearly overwhelming him. However, like his creator, Grond possessed a will of steel and refused to give up. As the calamitous battle raged, the tide shifted between each side. The Sporemounds were resilient, but could not hold out forever against Grond's attacks. Zang and Naanu both fell to Grond, and their bodies would over the ages transform into the Zangar Sea and Tanaan Jungle, respectively. By then the giant was weakened and scarred by the battle. Botaan sensed its opponent's weakness, but would need more power to defeat the giant. It leeched the life essence from the bodies of Naanu and Zang, absorbing the energies and growing to a monstrous size. It eventually managed to defeat Grond by entangling him in thousands of small vines that gradually burrowed into the cracks on his skin until they tore the wounds open, killing the giant.

The breakers and the primals
During the battle between Grond and the Sporemounds, pieces of their bodies had fallen to the earth and given rise to new types of creatures. From the seeds and roots of Zang, Naanu, and Botaan, creatures such as the genesaur sprouted, while colossals and myriads of elementals arose from Grond's remains. While Botaan and the genesaur began to retake the lands Grond had taken from the Evergrowth, Aggramar fused titan discs to the bodies of the colossals to empower them against the Sporemound and its minions. The titan suddenly felt a constellar dying somewhere in the Great Dark Beyond and left Draenor, never to return. Using guile, the colossals managed to lure Botaan away from the Evergrowth before attacking with their full might. For thousands of years they battled, with pieces of the colossals gradually breaking off and coming to life as the magnaron, who ignored the colossal's calls for aid and instead went their own ways. As the colossals' numbers were dwindling, they knew they had to take drastic action to destroy Botaan. Piling onto the Sporemound, they unleashed their energy in unison, creating a massive explosion that shattered the bodies of Botaan and the colossals, caused large swathes of forests to wither and instantly killed hundreds of genesaur. For one brief moment, the entirety of the Evergrowth trembled with the shared agony of Botaan's death. Then there was silence. Botaan's demise had destroyed the communal sentience of Draenor's wilds. Forests and jungles arose wherever fragments of Botaan's body fell to the earth, while the bulk of its body became the vibrant region of Farahlon.

The magnaron would gradually give rise to lesser creatures — the gronn, ogron, ogres and orcs. The common ancestry of these so-called breakers did not make them allies, but it did infuse them with a shadow of Grond's influence, and all of them were opposed to the verdant wilds. The genesaur and other plant-based life were known collectively as the primals, and they traced their lineage back to the Sporemounds; much like the breakers, many of them had arisen in the aftermath of Botaan's destruction, but while the numerous spores released from Botaan's corpse had weakened the creatures of stone, they had the opposite effect on plant life, granting existing plant species sentience and causing new beings to take shape in the jungles. Among these were the diminutive podlings and sporelings, as well as the intelligent and prolific botani. Faint memories of the Evergrowth lingered in the botani's minds, but they did not know the full truth of the Sporemounds or their battles with Grond and the colossals. Even so, what little the botani knew of the Evergrowth had a profound impact on their culture, leading them to revere the genesaur as gods due to seeing the larger creatures as echoes of the Sporemounds.

Gnarlgar and the Apexis
Many years later, a treant called Gnarlgar wandered the dense forests of Talador. From the genesaur, it learned of the Evergrowth, the Sporemounds, and the ancient past of Draenor. Gnarlgar eventually became aware of the arakkoan Apexis civilization, which it saw as an immense affront to nature and an even greater threat than the breakers. Gnarlgar departed Talador in search of a weapon to use against the Apexis, and discovered a massive fossilized root - one of the last remaining intact pieces of Botaan's body. The treant returned to Talador and rallied its botani followers, telling them that they would use the root to craft a new Sporemound, greater than any that had come before it, to cast the Apexis from their lofty spire. Gnarlgar planted the root deep within Talador and began a great ritual to nourish it, in which thousands of botani willingly sacrificed themselves to allow Gnarlgar to infuse their spirits into the root. When the Apexis became aware of the primals' war preparations, they quickly launched an attack on the heart of Talador but failed to destroy the burgeoning Sporemound, which Gnarlgar had named Taala, and lost nearly half of their forces. The Anhari order of Apexis proposed a solution in the form of the Breath of Rukhmar, a massive weapon that could channel the energies of the sun. As they began to work on the mechanism, Gnarlgar quickened Taala's maturation and ordered more botani to sacrifice themselves so that the Sporemound could be awakened before the arakkoa regrouped.

Finally, Taala stirred, and the primals began to march upon Arak. The Apexis realized they could not complete the weapon in time, but a small group of sorcerers of the Skalaxi order shrouded themselves in shadow and stalked into the forests to assassinate Gnarlgar. The treant sensed their presence and disposed of them, but not before he had been struck by a withering curse that soon caused his limbs to rot and die until he collapsed beside his assassins. Gnarlgar's death sent the primals into disarray, giving the Apexis enough time to complete the weapon. Just as Taala reached the Apexis spire, the Anhari ignited the weapon, instantly killing Taala and thousands of primals, finally extinguishing the Evergrowth forever.