Thraximundar plays well in a deck with a reanimation strategy. Use Fact or Fiction, Careful Consideration, Entomb, Buried Alive, Mental Note, or dredge effects like Darkblast for graveyard "card advantage." Add in reanimation spells like Stitch Together, Makeshift Mannequin or Zombify.
Or for fun, use him in a token generation + Threaten effects + sacrifice effects deck. Use cheap creature generators like Ker Keep or Puppet Conjurer and add sac effects like Ashnod's Altar, Bone Splinters, or Helm of Possession. Innocent Blood and Cruel Edict will intensify his slaughter-fest.
In Limited, Thraximundar is a finisher. Once you get him on the board, your opponent will have to focus his efforts against a hasty zombie that will most likely come across as a 7/7 as soon as he hits the board.
Your opponents will face Thraximundar with no warning, no chance to prepare. But the people of Alara knew what was coming—and were powerless to stop it.
The Rift Valley, Formerly of Jund
The Riftclan Tol Breot was lost in an unfamiliar land. They had been camped in a rocky enclave in the Rift Valley when suddenly the world shuddered, twisted, and then blasted them into this fetid hellscape. Half of their clan had simply vanished. In the confusion immediately following the shift, rot-skinned ogres assaulted them and slaughtered several more before the warriors killed them.
Now they were surrounded by grey, fleshy ground where nothing grew. There seemed to be no creatures of any kind save walking bags of bones that shambled past—easily killed, but providing no meat. The clan's chief, Breot, wouldn't let them eat the dead ogres because of the weeping sores covering their carcasses. Very soon, hunger would be their enemy.
Breot sent out a hunting party to look for familiar landmarks, but by the time they returned, half the clan had fallen ill with a horrible pox. Had they still been in Jund, they would have left the sick behind to make it easier for the healthy to survive. But Breot made the unexpected decision to keep all the survivors together and nurse the sick. No one questioned him. This land was too ominous and wretched to leave anyone to die. There wasn't even wood to build a pyre to honor those who had been killed. With a growing sense of unease, the clan stayed close to the camp, watched the sky for dragons, and wondered how they could return to the world they knew.
Greasy black clouds were rolling across the horizon when a black-haired boy stumbled into their encampment. He seemed barely human—the scrawniest grub of a child any of them had ever seen. One of the young mothers took pity on him and offered him some of their remaining tukatongue nuts. His dry lips cracked and bled in his effort to chew the hard shells.
"Where are you from?" Sonara asked the boy, clutching her own baby to her chest and passing him a bowl of rank water.
"Torchlight," he answered. When no one replied, he finished chewing and wiped the blood from his bone-white chin. He gazed intently around the fire circle through eyes that looked much older than they should. "You must flee. Quickly."
"The Riftclan does not flee," Breot informed the strange child, who stared back at the imposing chieftain without fear.
"Then your heart will be torn from your defiled body," the boy replied.
Had they been at home in Jund, Breot would have killed the boy instantly for such an insult. But the pale child seemed almost like an apparition, and his voice was so disconcertingly calm that Breot hesitated, his hand on the hilt of his obsidian blade.
And then they heard it. A rush of desperate, forlorn voices swept like wind through the camp as thunderous footsteps shook the ground. The clan's members staggered to their feet. Hardened and ferocious, the Riftclan were no strangers to death or suffering. They had seen their kin slaughtered by tooth, claw, and sword. But what swept over the ridge was beyond their realm of knowing. This was terror embodied, clad in spikes and standing over seven feet tall. Leading swarms of undead, Thraximundar charged down the hill and cut Breot down before the chieftain could raise his sword or utter a single word. As undead minions engulfed the clan, the boy scurried into the darkness, spreading news of the carnage like a plague upon the land.
He cannot be killed. He cannot be stopped. He is coming. Frightening tales passed through the line of refugees clogging the roads toward the Sun-Dappled Court. Where are the Knight-Captains? What is to become of us? Won't anyone help us? Weary and frightened, the refugees trudged forward because they didn't know what else to do. Late one afternoon, a battle-stained regiment of knights galloped through the stream of refugees. One of them proclaimed the good news of the battle of Tower Stele. A warrior-mage decimated an entire army of the hellish invaders! She will slay Thraximundar. Our borders will be safe once more!
Late in the afternoon, a caravan of Balmgivers from Topa reached the refugees with food and healers. That night, the name Elspeth was spoken around campfires and inside healing tents. She is as powerful as the angels. She will lead Bant in its time of need.
The next day, a black-haired boy appeared. The child moved between families, asking for a bite to eat and sharing harrowing tales of flesh-eating monsters and flesh-twisting necromancers. In hushed tones, he warned of the coming of Thraximundar: You would be better to cut your own throats than become one of his undead minions. Every kill just makes him stronger.
That evening, he shared soup with a blacksmith and his family who had escaped from the ruins of Giltspire.
"Knight Elspeth will be at Sun-Dappled Court," the blacksmith told his wife excitedly. "She's bringing an army of elves and catfolk. They will assault Thraximundar before he ever reaches Valeron."
"Thanks be to the angels," his wife Elleta murmured, followed by a chorus of their children's voices," Thanks be to the angels."
But the little boys narrowed his eyes. "Do not entertain false hopes," he told them quietly. "I was at the battle of Tower Stele, and Elspeth will not save you."
"Elspeth will save us," the blacksmith insisted. "She is the hope of our nations."
"Elspeth is gone," the boy replied, with a slight sneer on his lips. "She saved the Tower Stele, but committed a heinous crime in the process. Death was the only honorable course of action."
"Speak clearly, boy," the blacksmith boomed, looking into deep pools of black that were the boy's eyes. "What are you saying?"
"She threw herself on a pyre and scattered her essence to the winds," the boy replied. "I saw it myself."
The blacksmith turned to his wife, who sank to the ground and covered her face with her hands.
"You should tell everyone," the boy said sagely. "Before the false hope gathers in their hearts as well."
Antoris City, Formerly of Esper
Dragons besieged Antoris City. It was an infuriating situation, but not one that the mechanists and mages couldn't handle—at least so far. Around the clock, they kept a spell-wall around the city, which kept the marauding viashino away from the gleaming buildings and monuments. But the skies were more difficult to guard, and a broodmother and her young whelps had discovered that there was easy prey on pristine boulevards. Esperites were forced to keep to their houses during daylight hours. At night, the scullers from Darkreach District were enlisted to scour blood and rubble from the streets. But most citizens simply pretended that their city hadn't emerged on the side of a volcano and kept to life as usual.
As an arcanist, Lifris was more suited to the library than to guard duty. But all mages were required to man the spell-wall, so he did what was required of him. He paced back and forth along his section, wondering if the mage council had advanced beyond discussion to action. Someone had to figure out how to put Antoris back in Esper where it belonged and out of this dreadful lava pit. Still, the council was better than nothing. The mages had never agreed to work together before. They'd even pooled their etherium resources. It was quite remarkable, really. Despite the dire situation, the people of Antoris cooperated in a way Lifris never expected.
Something moved outside ethereal wall. At first Lifris thought it was a big cockroach—he'd see insects the size of boulders skittering around out there. But this creature didn't skitter, it crawled on its hands and knees. Then he saw pallid skin, black hair, and sad little eyes of a child.
Lifris should have consulted someone before he let the boy in, but he had a soft spot for children, and wouldn't want to watch anything suffer the filthy, bestial world surrounding Antoris.
"Gather all the mages," the boy told him. "Something wicked is coming. Your wall won't be enough to stop it."
Lifris stared at the boy, who looked so pitiful but spoke in such dulcet tones. He made sense, Lifris thought. Suddenly fearful, Lifris sprinted for the mages' tower, forgetting entirely about the spell-wall. When he was gone, the boy tapped the wall with his grubby finger, and a tiny rift opened in the shimmering barrier. By the time anyone noticed the break in the wall, the mages were too embroiled in argument to pay attention to the scullers who tried to warn them.
The boy watched from the hill, until the smoke rising from the city blocked his view of the destruction. With each life taken, he could feel the Maelstrom expand with more energy—just as he wanted. Of course, there would have been easier ways to accomplish such destruction, but it would haven't have been nearly so whimsical. Besides, Thraximundar was such a beautiful creation, so perfectly suited to mindless carnage, that Nicol Bolas didn't mind letting him run wild as he pleased—with just a gentle nudge in the right direction. The dragon let his illusion of the little boy evaporate into the acrid air and resumed his natural shape. The planeswalker Elspeth wasn't really dead, but she would cause him no more trouble in Alara. With Antoris a smoldering ruin behind him and Thraximundar sweeping toward the green jungles of Naya, Bolas spread his wings and soared into the darkening sky.