You think you can defeat me? Pathetic little scum! I am the Warchief of the Horde, I am the Lich King of the Scourge, and I will be the reaper of your soul!
When Sargeras started raising his orcish Horde to assault Azeroth with, Grommash Hellscream was one of the first to volunteer. He quickly became known as a ferocious warrior. His "surname" is due to his extremely ferocious battlecry.
When the orcs stepped through the Dark Portal, they were immediately seized by Deathwing, and became his personal army. Grom followed the rest of the Horde, but his true allegiance was with the Legion. When the orc were "disbanded" and ended up in labour camps (or dead, if they were fortunate), Grom tried to re-unite the orcs, but he was unsuccessful.
The Reunited HordeEdit
When the young orc Thrall did what Grom was unable to, the ferocious warrior joined up with the new Warchief. He became his lieutenant. After they had ventured to Kalimdor, Hellscream encountered the surviving night elves, weak due to their abandonment. They asked for help, but instead, Grommash Hellscream slaughtered them all. Not long after this, he betrayed and killed Thrall, becoming the new Warchief. He orders the construction of a new Dark Portal, with which to contact Sargeras. In return, Sargeras makes Grom the Lich King, and gives him command of a vast undead army. This attracts the attention of Deathwing.
Grom vs. ArthasEdit
The draconic war-host, led by the brilliant general Arthas Menethil, scored great victories, and succeeded in reaching the orcish capital city of Legionmar. Here, he almost managed to crush the Horde forces, when Hellscream decided to enter the fray in person. The draconic soldier fell like brittle sticks under the relentless assault of Hellscream, drawing power directly from Sargeras, and Arthas had no option but to challenge him in personal combat. Considering himself invincible, Grom accepted, something he was going to regret. Arthas struck with the fury of a thousand dragons, battering down onto his enemy with his powerful hammer Wyrmfury, and the Lich King did the same with his Gorehowl. It was a very even match, when suddenly, Hellscream struck his gigantic axe into the Dragon Knight's back. Thinking himself to be the victor, he raised his arms and cheered, just enough for Arthas to remove the axe from himself and chop it straight into his adversary's chest. Stunned by this surprise assault, Hellscream had no chance to dodge the blow from the Wyrmfury as it bashed his brains out. Not long after, Arthas too died from the injuries he had received. In death, the Lich King ascended to become an eternal, but it would take time before he could regain his power.