Major Story Arcs
Nova Prime ruled during the golden age of Cybertron and was the predecessor to Sentinel Prime. He wanted expansion for he believed Cybertronians were above all other forms of life and that the universe should be somewhat molded in their image. So he gathered a crew, which included Galvatron and others, and they set off in a ship called the Ark to begin the expansion. However, when they traversed near the Benzuli Expanse Galvatron – believing his destiny lie there- sabotaged the ship and sent it into the expanse, trapping everyone within the dead universe that lay beyond. In the dead universe, Nova Prime and Galvatron came across an ancient and powerful force known only as the darkness. Sensing the Matrix vacuum within Nova, the darkness chose him to be its possessor and Nova Prime became Nemesis Prime. With the power of the darkness, Nemesis Prime made the rest of the crew into his heralds to do his bidding. Nemesis Prime sought to cause an expansion to merge the dead universe with the universe from which they came. To this end, he sent out Galvatron to clear away everything near the Benzuli expanse, retrieve Thunderwing, and stop the Reapers from destroying the Earth, while he has Jhiaxus turns Nightbeat into an unwitting probe on Gorlam Prime with the intent of having him kill Optimus Prime when the time comes.
With the help of Jhiaxus and Cyclonus, Nemesis Prime has several nega-cores activate on various planets - all protected by guardians which include Monstructor, Thunderwing, and Sixshot - to ultimately begin the expansion to merge the two universes into one and ultimately returns to the universe from which they had come. However, Nightbeat finds his way back to Gorlam Prime, and although Jhiaxus activates the probe he placed in him earlier to take control of him, Nightbeat is ultimately killed by Hardhead. Because of this, Nemesis Prime realizes that he must now get directly involved - something he had hoped to avoid at all costs until it was too late to affect the expansion in any way - and kill Optimus Prime himself. Nemesis Prime then heads to Garrus-9, kills all those who stand in his way, and ultimately comes face to face with Optimus. Upon meeting each other, Optimus asks Nova why he's doing this and what happened to him and Nemesis Prime responds by revealing to him the darkness that he possesses and how unlike the Matrix - which he views as being a leash which limited what they could do - it has no limits. He then attacks Optimus, badly damaging him, and tells him that the darkness will grant him dominion over everything that survives from the fusion of the dead universe and their universe. He then prepares to finish Optimus off, but as he approaches him the Darkness transfers from him into Optimus, who then explains that the Darkness is more like the Matrix of leadership that he thought as just like the Matrix, the Darkness seeks to pass from Prime to Prime and it views Nemesis as being yesterday's Prime. Optimus then says that this is the reason why Nemesis Prime was hoping to avoid getting directly involved and why he knew that he [Optimus] had to die. Nemesis Prime gets infuriated by this and attacks Optimus from afar. Optimus tries to beg him to stop and undo what he has done as he is still a Prime, but Nemesis ignores him, saying that Cybertron will be the template for a new universe and that it is their destiny. Optimus tells him that he he will stop him, and Nemesis Prime takes this as arrogance and tells Optimus that he reminds him of Galvatron and as he says this, Galvatron, who had secretly been watching the confrontation between Optimus and Nemesis, no longer sees reason to serve Nemesis since he no longer possesses the Darkness, so he shoots Nemesis Prime in the back, killing him.
Heart of Darkness
Nemesis Prime is resurrected and remade by D-Void in the Dead Universe and he’s sent out to reclaim the Heart of Darkness. When Galvatron arrives on Dykayra sensing D-Void’s presence there, Nemesis Prime emerges from a trans-dimensional gate and tries to kill Galvatron as revenge for his betrayal. Galvatron and his forces manage to quickly overpower Nemesis Prime with their firepower, but then the D-Void takes over Nemesis Prime and makes him stronger. Nemesis Prime then begins feeding off of the energy of Galvatron’s army and Galvatron sends Cyclonus and Scourge to gather the rest of his forces while he keeps Nemesis Prime busy. Just as the D-Void possessed Nemesis Prime is about to finish Galvatron off, the main forces arrive and drive him back into the trans-dimensional gate and Galvatron then shoots the portal, destroying it.