The one thing that is so great about Bleach is that sometimes the good guys have to get a bit lucky to defeat their enemies. Ichigo might be strong but it usually takes the combined forces of the Shinigami to help defeat the strongest foes. This gives it a sense of realism where the villains are actual threats to the existence of the Soul Society.
During the Thousand Year Blood War arc, the Soul Society didn't just face a single threat but, instead, had to handle an empire dedicated to their destruction. The Vandenreich consisted of Quincy who believed failure to overthrow the Soul Society would lead to their extermination. Such a belief allowed them to fight like there was literally no tomorrow. With all that said, were they really the greatest threat the Soul Society has faced?
10 Greatest Foe: 1,000 Years Of Preparation
Time can be a powerful tool in the hands of those who know how to squeeze the most out of it and those who have zealot-like hatred towards something or someone can really pose a threat like no other.
After the Soul Society nearly wiped out the Quincy 1,000 years ago, the remaining Quincy hid in the shadows, not just biding their time but creating an empire that would absolutely overrun the Soul Society when the time was right. Their years of preparation proved beneficial with their initial wave presenting devastating effects on the enemy.
9 Worst Foe: Not Enough Sternritter
The Vandenreich used their time in the shadows properly, with their initial wave of attack resulting in a key victory in the war with the Soul Society, their overall numbers that were powerful enough to inflict damage was minuscule compared to that of the Shinigami. The Sternritter consisted of twenty-eight of the most powerful Quincy in Yhwach's army.
These Quincy proved they could stand toe-to-toe with the Captain-level Shinigami's but, unlike the Shinigami, the Sternritter's numbers were few, resulting in each loss being more devastating than the loss of a Shinigami Captain.
8 Greatest Foe: Auswählen Technique
While the Shinigami are powerful enough to defeat many of their more formidable enemies on their own. There are a few occasions where they have to use the power of their Bankai as their finishing move, annihilating their enemies with extreme force in the process.
Sadly, the Quincy lacks such a powerful tool, so to make up for it Yhwach uses a technique called Auswählen as a sort of power redistribution, siphoning off power from the weak to rejuvenate the strong. Though, it comes at the cost of the lives of the weaker Quincy.
7 Worst Foe: Quincy Are Nothing More Than Highly Trained Humans
Shinigami are one of the stronger races in the Bleach Universe. Their strength along with the use of their Zanpakutō makes them close to invincible to beat. Add that with a body that is basically immortal, and you have the makings of a formidable foe. Unlike the Shinigami, the Quincy are basically the equivalent of humans with special powers.
They are mortal beings who normally do not have the power to fight one-on-one with the power and might of a Shinigami foe. Though, there are exceptions like the Sternritter's who can bring down even the most powerful Shinigami.
6 Greatest Foe: The Medallion
If you're a Quincy and you're going against a group that nearly annihilated your people 1,000 years ago, to survive, you would have to create a weapon that could match the power of their enemies. Luckily, for the Quincy, they have a device called the Medallion that can strip a Shinigami of their Bankai through a means called medalize.
This effect allows the Quincy to steal the Shinigami's Bankai and use it against its master. During the initial wave of the Vandenreich's attack, the Medallion proved valuable in giving their army an advantage in the fight against the Shinigami.
5 Worst Foe: Underestimates Their Enemy
Probably the worst mistake any army can make is underestimating their enemy's capabilities. In some real-life instances, this very nature has led to the demise of empires. The Vandenreich's full-proof plan to conquer the Soul Society was brilliant and at first, placed the Shinigami at a noticeable disadvantage in the fight.
Yhwach believed himself to be invincible after consuming the Soul King. However, the Vandenreich and their leader Yhwach severely underestimated the capabilities of Ichigo Kurosaki, resulting in the Vandenreich's annihilation, along with his own defeat at the hands of Uryū and Ichigo.
4 Greatest Foe: Yhwach Has The Ability To See The Future
Humans tend to think of the past, present, and future as being on a linear path. Each action leading to one future with all other actions not taken having no effect on the timeline. However, in Bleach the future does not work in this manner. Instead of one inevitable fate, it has many different possibilities.
Yhwach's omni-precognition allowed him to witness all the different paths his life was on, a gift that seemingly made him invincible since he could clearly just avoid the paths that ended disastrously. Though, in the end, he was still defeated by Ichigo.
3 Worst Foe: Cleansing Of Lesser Quincy Weakened Their Numbers
There is a point of view that believes cleansing the weak to make room for the strong will ultimately lead to greater success in battle. Then there is the view that even the weak can be strong with numbers.
Yhwach was under the impression that for his army to succeed he had to purge the weaker Quincy from his ranks so that the stronger ones could ultimately thrive. This makes sense to a certain degree but, unlike Yhwach, the Shinigami prefer a balance of strong and weak soldiers, allowing them to overrun the Quincy ranks.
2 Greatest Foe: The Quincy Fight For Survival
The Shinigami might be considered the good guys in the eyes of Bleach fans but even the strongest advocate for the Soul Society must admit that they have done some pretty evil stuff over the ages.
Acts that have sometimes come back to haunt them in the future. After trying to exterminate the Quincy 1,000 years ago, they left the remaining Quincy believing that another defeat would lead to their annihilation at the hands of the Shinigami. History of the Shinigami's actions seemed to prove this logic correct resulting in the Quincy fighting for their survival.
1 Weakest Foe: The Sternritter's Blind Loyalty to Yhwach
In war, sheer numbers can change the outcome of battles. Even against a more well-trained and powerful enemy. That said, Yhwach had a Darwinian approach when it came to the Sternritter.
He not only rid the ranks of the weakest, but he also imposed brutal rules that if one was defeated in battle or squabbled with their comrades they might find themselves on the chopping block. Yet, even though, they were treated poorly by Yhwach, they still followed his commands blindly, instead of helping him find more successful alternative paths.