A loyal follower of the Egyptian God of death, Seth, Grog led his armies to assassinate the Asgardian God of thunder, Thor after his return to Earth. On the Avengers floating headquarters called Hydrobase, Grog, and a horde of soldiers, made their first strike. Thor was aided by his comrades, the Captain and the Black Knight, and the three of them managed to defeat Grog and all of Seth's men. Grog was carted off to the Vault by the Black Knight, but he would soon be free again.
After a second attempt, by Seth, to take the life of Thor by creating a group of super humans called Earth Force, Thor went to the Vault to question Grog of his master's whereabouts. Not alone, Thor traveled with fellow Asgardian Hogun, the Grim, the Black Knight, and the reformed Earth Force, but Grog was not intimidated by the forces that massed against him. Once freed from his shackles, Grog summoned a portal back to the territory of Seth and escaped his foes. Thor had planned on Grog's escape in order to follow him into the realm of death so he could face the Death god, but Grog had been ready for Thor and his allies by having a welcoming party ready to greet his enemies once they were through the portal. The heroes fought valiantly, but were ultimately overwhelmed by Seth's troops. Thor, too, fell before his enemies when Balder, the Brave, summoned Thor's powers back to Asgard to help defend the Golden City against another wave of Seth’s unrelenting attack. Grog reveled in his triumph over the Thunder god.
The victory was short-lived, however, because with the seeming death of Balder came the return of Thor's powers. Thor wasted no time in dispatching his foe and damaging the stronghold of Seth, the Black Pyramid. Grog, now bound and at the mercy of his captors, knew the fortress better than his enemies and got away using a secret door in the pyramid’s corridors. However, he soon returned with reinforcements to crush Thor once and for all. His strategy did not go as planned for the combined might of the Asgardians, Earth Force, the Black Knight, and the other Egyptian gods proved to be too much for Grog and his men. Unwilling to admit defeat, Grog resurfaced for the final time as Surtur, the fire demon, battled Thor. He shouted boasts of his recovery and his opponents' inevitable defeat, but it was he who met his demise when Surtur used the remains of the Black Pyramid as a weapon against the mighty Thor. Throwing the citadel at Thor, the Black Pyramid was destroyed by Thor's mallet, Mjolnir, leaving Grog and his remaining forces to be crushed inside.
Grog proved to be highly resilient and was once again at his master's side during yet another attempt to bring the Thunder god to his knees. Grog, along with Seth's other servants - Gog, Magog and Scarab, were unleashed upon the population in order to bring Thor out of hiding. Once successful, Grog and the others would attack in unison to annihilate Thor. Grog, however, had other ideas. Possibly still suffering humiliation from his last defeat at the hands of the Asgardian, Grog wanted to be the one to destroy Thor without help from anyone. Having been told Thor had a broken spirit from his recent banishment from Asgard for killing his grandfather, Bor, Grog thought it would be an easy victory. Unfortunately for the God-Slayer, he fanned the fires of Thor's rage, and once more, it was Grog who had been defeated. Grog would be punished for ruining his master's plan, and Seth cut off Grog's hand, leaving him in the image of his master.