One of the Orc Chieftains of legend, Grom Hellscream was the leader of the Warsong clan. While his clan was spared the defeats of the Second Great War, he was used with effectiveness by Ner'Zhul in the aftermath of the second war. His forces combined with that of the Bleeding Hollow clan and Kilrogg Deadeye were used in strategic hit and run raids designed to retrieve some of Azeroth's most powerful magical artifacts.
Grom Hellscream is playable in missions of Warcraft II: Beyond the Dark Portal. His clan is also clearly evident throughout the human campaigns. His missions in the Warcraft II expansion include destroying a rogue Ogre Mage Warlord, Mogor, and the Temple of the Damned that this Ogre defended.
With the destruction of their only passage home and the successful vanquishing of the Orcish strike forces, Grom and the Warsong clan are forced into hiding in the wilds of Lordaeron. They eke out an existence on the edge of human civilization for nearly 15 years.
Grom is all of this time forced to fight the demonic curse that has left him weakened and listless. Where other Orcs give into this malaise, Grom fights it to the end of his days. As the number of free Orcs is diminished by conflict and old age, their situation looks more and more hopeless. The young and weak are unable to thrive in this harsh environment and the day of reckoning looks to be closing in on the Warsong clan.
Then Grom has a young Orc named Thrall introduced to him. Inspired by Thrall's courage, strength and mercy, he accepts the young outcast and teaches Thrall more of the ways of the Orc nations. When the humans searching for Thrall get too close, Thrall leaves his side with Grom's necklace as a symbol of the trust placed in Thrall by Grom.
The Warsong clan lead by Grom is reunited with Orgim Doomhammer and Thrall's lost clan, the Frost Wolves. Battling against the Human internment camps surrounding the stronghold of Durnholde, the two clans set about freeing and reinvigorating the Orcish nations.
While the Orcish horde is looking for settlement land in Lordaeron, they are instructed by the new Warchief Thrall to journey across the seas to the strange new continent of Kalimdor.
When Grom begins to again feel the twinge of the demonic curse, he proves to be unable to resist the sweet nectar it promises him. After disobeying orders from his Warchief, he is given what was presumed to be an easy, out of the way mission to clear land and gather lumber for the new Horde. Instead, he angers the Night Elven demigod Cenarius.
To preserve his clan from this new threat, Grom again samples the demon Mannoroth's blood in a defiled fountain. Driven again by the demonic energies, Grom attacks and destroys the demigod Cenarius's forces and even the demi-god himself is no match for the enraged Orc chieftain's might.
Totally taken now with the demonic power, Grom turns against everything he knew from Thrall's reinvigoration of the Horde. He turns even against his good friend and warchief, completely a tool of the burning legion's desires. Only a joint rescue effort by Thrall, Cairne Bloodhoof, and Jaina Proudmoore can save him from the demonic blood that corrupts his thoughts and actions.
As he is being freed again from the demonic corruption, Grom tells Thrall the horrible truth of the Demonic curse. The Orc Clan Chieftains had willingly taken the bloodlust offered by the Burning Legion. They were not as much cursed as doomed by the willing choices made by their power hungry leaders.
The redemption of Grom Hellscream is close at hand however. Enraged by the awful secret of the Orc's spiral into bloodlust and hate, Thrall leads Grom into a canyon to seek out the demon Mannoroth and end the corruption that was once again visited on them. A mighty blow from Thrall is shrugged aside by the massive demon, whose counterattack leaves the young Warchief stunned and unconscious. Driven by sheer force of will, desperation, and desire for an ending to his suffering, Grom Hellscream makes his last charge. His axe strikes home and the resulting destruction of the demon lord cause a massive explosion.
Unable to avoid the explosion, Grom is mortally wounded by the terrific energies unleashed by Mamoroth's passing. His head held in his friend Thrall's hands, the burning flames of the demonic corruption are quenched. Grom turns to Thrall and tells him he is free of the corruption that has stalked him. Then his body surrenders to it's wounds and Grom Hellscream's sacrifice is fully realized.
Just How Old Is Grom Hellscream?
Grom Hellscream is an interesting case study in the changing timelines of the Warcraft universe. In the Warcraft III manual, Grom is dated at age 46. He is also listed as "…one of the first orcs to fall victim to the demons' curse on his race." Now this is very interesting, because that means that Grom has survived from the initial Burning Legion impressions on the orcs, clear through both great wars to the beginning of the Reign of Chaos.
In the original game's manual, we get the history of the world of Warcraft to the present date. This history is as transcribed by Garona of the Shadow Council. She details the initial portal rifts as taking a period of time for the Orc Warlocks to secure passage for a single clan.
At this point, we can start a timer. Garona tells her audience that the Shadow Council had made a "… request that they cease their war [on other orc clans] for one year." The Orc clans push through a host of warriors that attack the Stormwind kingdom's seat of power, Stormwind Keep. There they are pushed back by the magics of the human mages. Then, according to Garona, "It has been some fifteen years since this costly decision altered the course of our destiny." She has described there 16 years of history.
Between the First War in the game Warcraft: Orcs and Humans and the Second War in the game Warcraft II, it is well established that six years pass. That makes 22 years since the opening of the rift.
Since we can't seem to date the length of time between the end of the Second War, we'll have to use the dating from the Warcraft III manual.
Here's where it gets interesting again. According to the Warcraft III manual, Thrall is discovered "during the dark days of the First War" and that he escapes from Durnholde, "Nineteen years passed…" In the novel "Lord of the Clans" it takes Thrall about one year from his escape to his bittersweet and triumphant return to his childhood home. That gives us 20 years from the end of the First War. In this timeline, Grom would have had to be chieftain of his tribe at a maximum age of ten years old.
Of course, what does this all mean? Nothing. Like the Warcraft maps, the Warcraft time line is Blizzard's to change however they like. 
- Full name: Grommash Hellscream
- Best friend and advisor of Warchief Thrall
- Grom and Thrall confronted Mannoroth to destroy him near the end of the war against the Burning Legion. Grom was able to bury his axe deep in the creature's chest, but the act unleashed the horrible magic within Mannoroth, and though Mannoroth was killed by the act, so was Grom.
- Grom's body was buried in Ashenvale, in the area now known as Demon Fall Canyon.
- Grommash Hold in Orgrimmar is named for him, and just outside is the armor of Mannoroth (complete with axe-hole) with a plaque dedicated to Grom.