The Death Eaters manned the police of Antarctica, the Ministry itself & all educational sources in which was linked to all kinds of opposition, The first targeted opposition was the same that took down the Inquisitorial Squad, The Penguins & the only educational source linked (in fact, it's the only educational source in Antarctica) is Antarctic Penguin Middle School
The Death Eaters charged into the Ministry to claim it's power, but the Ministry rebellion act happened just at the right time to stop the Death Eaters, who escaped realizing the danger of another arrest.
The Death Eaters returned to the school, not for an education, but revenge. Voldemort uncovered the Mask of Dark Earth, He decided to take over the school & kill the Penguins. The Death Eaters end up declaring war on the school. Riddle later dies from draining so much life into the Mask, which was destroyed.
The Death Eaters that survived the Second War were hunted down by the Ministry to be sentenced, Those who weren't captured died of starvation, lack of fresh water, wild animals killing them, Those who were rounded up, but fought were killed & those who were caught & were scared to be killed ended up being killed by being eaten by a wampa.