After Hitler is appointed chancellor and calls for another election, Hermann Göring, wanting to curry favour with Hitler, attempted to dispose of any possible opposition for the upcoming election. The first target was the Communists, who Göring believed were an existential threat to the German State. He and a group of soldiers raided the Communist party headquarters, looking for evidence of a violent Communist uprising. Having found nothing other than inherently revolutionary sounding Marxist literature, Göring decided to make it seem as though it was beginning.

Thankfully, the fire was quelled but, almost immediately, the Nazis began playing the blame game, pinning the fire as a Communist plot. They immediately called upon Hindenburg to issue the Reichstag Fire Decree, calling for the suspension of habeas corpus, freedom of speech and freedom of press. It is strongly believed to this day that the burning of the Reichstag was a plot by Göring in an attempt to demonise the Communists and uplift himself in the Nazi ranks. An attempt that, unfortunately, worked.
Göring, now having ample reason to arrest political opponents, called upon the Stormtroopers (SA), the Nazis Paramilitary wing, to help with the muscle of the operation, the SA being lead by Ernst Rohm. Members of the Communist party were rounded up and arrested, heads of the party, such as Ernst Thälmann, were captured, their hiding places being ratted out. Thälmann was shot on a personal order from Hitler in 1944 at Buchenwald Concentration Camp. In all, over 20,000 people were arrested, simply for the crime of having a political belief.
That election, the Communist lost 19 seats, whilst the Nazis gained 92. The SPD, who had leftist leanings, also lost votes.

Due to the outrage, both in and out of the Reichstag about the fire, an act was passed that allowed the Nazi Cabinet of Germany and the Chancellor to govern and enact laws without the consultation of the Reichstag or President Paul von Hindenburg.
In addition to the procedure prescribed by the constitution, laws of the Reich may also be enacted by the government of the Reich. […] Laws enacted by the government of the Reich may deviate from the constitution as long as they do not affect the institutions of the Reichstag and the Reichsrat. The rights of the President remain unaffected. […] Treaties of the Reich with foreign states, which relate to matters of Reich legislation, shall for the duration of the validity of these laws not require the consent of the legislative authorities. The Reich government shall enact the legislation necessary to implement these agreements.
Excerpts from the Enabling Act of 1933
The Reichstag had been controlled. Now it was time to subjugate. In July of 1933, the Law Against the Formation of Parties was passed. It was only 3 sentences long.
The Reich government has passed the following law, which is hereby promulgated:
The National Socialist German Workers’ Party [Nazi Party] is the only political party in Germany.
Anyone who undertakes to maintain the organisational cohesion of another political party or to form a new political party will be sentenced to imprisonment for up to three years or jailed from six months to three years, unless the act is punishable with a higher penalty by other regulations.
The entirety of the act
It was signed off by Minister of the Interior, Wilhelm Frick, Minister of Justice, Franz Gürtner, and Hitler himself. That September, another “election” was held in which voters were simply given a list of Nazi Sympathisers but who were not members of the party, and were asked if they were for or against the Party. The election was not secret and multiple people were punished for voting no or not voting at all. The Reichstag was now merely a stage for Hitler’s speeches to a crowd of yes men. Democracy was dead and Hitler killed it.

Hitler, however, had higher aspirations. He needed all political dissent crushed as fast and effectively as possible, so he called upon Heinrich Himmler. Himmler had been the Reichsführer of the SS since 1929, the SS being another paramilitary group made by the Nazis. The difference between the SS and the SA was firstly the sheer commitment they had to the Nazi Ideology, that the Aryan Race was truly superior to all other races, and secondly their brutality, both sentiments shared by Himmler. He opposed more conservative Nazis, who believed that the Rule of Law was required to arrest political opponents. Himmler had other plans.
Himmler, now following the will of Göring, weaponises new laws to arrest the Nazi Opponents, under the pretence of Protective Police Custody. Himmler used this very liberally, arresting over 100,000 political opponents. Now needing a space to put these prisoners, he began the opening up of concentration camps, which would be guarded by the SA and the SS would rule. The standard police were not present. As a result, mass executions of political prisoners were organised. It is suspected that at Dachau alone, 40,000 people died between 1933 and 1945, many of whom were Communists, Social Democrats, Trade Unionists and Jews.

Himmler expanded the SS to fundamentally replace the police all across Germany. Himmler also offered a handpicked group of SS members to the highly paranoid Hitler to be his personal bodyguards, buying his complete loyalty to Hitler.
Finally, Göring, in an attempt to counter the influence of the SS, established the Gestapo, a secret police who would report on any anti-Nazi activity and have those who partook in it arrested. However, oversight of the Gestapo was eventually passed to Himmler in April 1934, who appointed Reinhard Heydrich, a ruthless fanatic, as director of the agency. Heydrich ended up playing a key role in the creation of the final solution, which led to the deaths of six million Jews.

In just 6 months, Hitler brought down the parliamentary democracy, fundamentally reshaped the rule of law and began polluting the minds of the German people through state owned newspapers.
One outstanding issue, however, was Ernst Röhm. Röhm, still currently head of the SA, had ambition beyond just running an auxiliary force. He wanted a Nazi army all to himself and felt he was being upstaged by the rapid expansion of the SS and founding of the Gestapo. He went behind Hitler’s back and began making moves within the army, then controlled by President Hindenburg. Not only that, but Röhm was quite openly gay, something that was strictly illegal under socially conservative laws in Germany and disgusted the Nazis. Hitler believed that the open secret that Röhm was a homosexual, something that he had previously defended, now could be an issue to his reputation, as a leader of a pure Germany. In addition, due to the violence and chaos on the streets, Hindenburg immediately requests that Hitler stops the SA or he will be removed as Chancellor. Röhm was an issue that Hitler needed to take care of and fast.
On the 30th of June 1934, Hitler invited Röhm and many other SA generals to Hotel Lederer in Bad Weissee. Once they were all gathered there Hitler and many SS officers stormed the building and arrested the officials. Hitler gave Rohm the option of him killing himself or he would be executed. Rohm chose to be executed and was shot on the 1st of July in Stadelheim Prison.
This carried on until July the 2nd, killing many, including former German Chancellor, Kurt Von Schleicher, anti-Nazi journalists, Fritz Gerlich and Edgar Jung, Competitor for Chairman of the Nazi Party, Gregor Stasser, a man who attempted to stop the Munich Putsch, Gustav Ritter von Kahr and many more. Once the purge was done with, Hitler claimed that Rohm had been trying to overthrow the government, which justified the killings to the public. He also claimed that there were only 61 deaths, when in reality it could’ve been anywhere between 85 and 1000.

On the 1st of August, a law was made that if the President were to die, his powers would be merged with that of the Chancellor. President Hindenburg died the next day, giving Hitler full control of Germany and its people. When greeting himself to his new army, Hitler made them swear an oath to him and not the country. The Nazi age had begun.