Is it okay to declare someone a living example of cause and effect? I think I have enough to justify that claim and it's still an interesting topic for what it's worth.
Dong Zhuo was a tyrannical Chinese warlord who can be considered either directly or indirectly responsible for the fall of the Han Dynasty and the many bloody battles that followed lead by the forces of Wei, Wu and Shu during the Three Kingdoms Era (known to most as the Romance of the Three Kingdoms on a fictional note). He was a hedonist and a sociopath who used and abused his power to fit his idea of "paradise" (basically paradise for him and no one else).
After years of corruption by various eunuchs and an inept emperor, the Yellow Turban Rebellion rose up and was inevitably destroyed by the troops by Hu Jin who is then killed by the eunuchs who are in turn slain by Yuan Shao. During this chaos the emperor Shao and the prince of Chenliu vanish.
They end up in the hands of Dong Zhuo who seized control under the guise of protecting the emperor. Dong disposed of Shao and instilled Emperor Xian who he controlled like a puppet. The reign that followed was brutal as innocents were put to death and those not rich enough suffered constantly.
After two assassination attempts, a full scale war began. However Dong had one trump card: his adoptive son Lu Bu. Lu Bu was a god among men who no one could defeat. As long as Lu Bu remained by Dongs side no one could touch him.
But a conflict grew between the two. Lu Bu, already losing patience with Dong Zhuo, fell for a maiden who his father also lusted after. The maiden convinced Lu Bu to betray his father and Lu Bu slew him, ending the tyrants madness.
Lu Bu attempted his own campaign against the emperor but was betrayed and executed by Cao Cao of Wei. Dong Zhuo's reign was short but the impact was great. He's generally considered the straw that broke the camels back as his death lead to the fall of the Han Dynasty and 3 men all with their own idea of paradise stood up and fought amongst themselves.
It's possible that Dong Zhuo is what caused these 3 men Liu Bei, Sun Jian and Cao Cao to stand up for their beliefs. What followed lead to the death of countless men and ended in pointless tragedy. Historically speaking none of the men "won" Cao Cao died in his bed, Liu Bei went mad after the death of his best friends and Sun Jian died during the campaign to overthrow Dong Zhuo. His sons Sun Ce and Sun Quan tried to replace him but Ce died of an illness and Sun Quan was killed years later during an invasion by the "true winners" the kingdom of Jin.
Perhaps had Dong Zhuo not committed his many atrocities the men may have worked together? Maybe they wouldn't have decided to act at all? History agrees that Dong Zhuo played a huge part in all 3 men's motivation but if he wasn't here who can say? The Han Dynasty was on its knees and chances are Dong Zhuo simply sped up the process.
On a final but by no means uninteresting note, Dong was so hated that they dragged his corpse out into public,set it alight and anyone who tried to put it out was killed on the spot. He was so fat that his corpse burned for three days straight. In the middle of winter.
Anyone who carried the Dong name was hunted down and killed including Dong's elderly mother who plead innocence as she was brutally murdered. That's how hated Dong Zhuo was by the people of China.
As I've said before,Dong Zhuo COULD have been the cause of the following war. His actions provoked a large number of men to stand against him and after his death they began to focus on one another. Corruption ran deep through the country at the time but Dong Zhuo was far from subtle about it.
It's an interesting aspect of history that eternal question of "What Could Have Been?" but that's exactly it. What could have been is a cruel aspect of life as reality will always ALWAYS disappoint to what we can imagine. And considering how many people died as a result of the aftermath it is a pretty disappointing reality.