The Bleach universe is divided into the human world, Soul Society, Hueco Mundo, and Hell. All these places have strong individuals, who usually end up joining units such as the Soul Reapers, Espada, Quincy, and Fullbringers.
These fighters are exceptionally skilled, due to years of intense training. The Bleach universe is filled with characters capable of easily wiping out cities in the blink of an eye. The strongest warriors in this universe also happen to be the oldest, proof that nothing trumps experience in bleach.
10 YORUICHI SHIHOIN
Yoruichi was a princess of the Shihoin family, one of the four great noble families in the Soul Society. She relinquished all her titles before departing for the human world. After finding out her friend Kisuke Urahara was being set up, she helped him escape from captivity, where he then headed to the human world. Now a criminal, Yoruichi quickly renounced her titles and settled quickly into life on earth with Urahara. Yoruichi has consistently shown herself to be a top tier fighter in the Bleach universe. Her speed makes her a threat to any opponent and she might actually be the fastest character in Bleach.
9 ICHIGO KUROSAKI
Ichigo Kurosaki is the strongest part-time Soul Reaper to ever exist in the Bleach timeline. His unique ancestry accelerated his development and he quickly became one of the strongest fighters around. Not one for deep strategizing, Ichigo is known for his bullish and abrasive fighting style. This often manifest itself in his famous Getsuga Tensho technique, where his Zanpakuto condenses and releases Ichigo's spiritual energy at his opponent. This move, even though simple, is devastatingly powerful, as those who've faced it would know.
8 KENPACHI ZARAKI
As the current holder of the title of Kenpachi, Kenpachi Zaraki stands as the Soul Society's most physically intimidating force. Kenpachi does not rely on tricks or any special kind of ability. Zaraki has always been an all-out brawler, a man absolutely obsessed with winning and coming out on top. For much of the series, Kenpachi suppresses his powers so that he could enjoy his fights but, towards the end, he unleashed his true power. With his Bankai, Kenpachi is able to deal insane amounts of damage. However, his lack of control in this form currently limits his ability.
7 LILLE BARRO
Lille Barro was a loyal member of Yhwach's personal guard and was the first Quincy to receive an ability from Yhwach. This went to his head, and he would often proclaim himself to be Yhwach's greatest ever creation. Despite being an experienced and dangerous combatant, Lille is often caught off guard by events he failed to predict.
This makes him weak to adaptable fighters, but his deadly sniping skills means he's still a major threat. His 'Monk of Destruction' form grants him intangibility and this, combined with light beams, makes him a handful.
6 ASKIN NAKK LE VAAR
Askin can often be sarcastic and unpredictable in his behavior, leaving his comrades frustrated. He takes this same sarcasm and unpredictability with him into battle, which often gives him the upper hand. Though playful in battle, Askin is also deceptively clever and is always on the lookout for his opportunity to strike. Askin's "Deathdealing" ability means he often only needs one chance. His Monk of Destruction form was strong enough to combat Yuroichi, Urahara, and Grimmjow. Even though he did eventually lose, for a long while he held his own.
5 SHUNSUI KYORAKU
Even prior to becoming the Captain-Commander of the Soul Reapers, Shunsui Kyoraku was a man famous for his impressive sword skill and massive spiritual power. His attitude is often relaxed and carefree which often annoys his lieutenant, Nanao Ise. But, much like everyone else, she knows that Shunsui is one of the wisest and most experienced warriors in Soul Society. His Zanpakuto can sometimes be moody and childish, and this manifests itself in its abilities. Anything that gets within the range of Shunsui's spiritual power has to play a game, where Shunsui gets to decide the rules. His Bankai takes this to a different level, which makes him a contest for even the most powerful of combatants.
4 ICHIBE HYOSUBE
Ichibe Hyosube holds the epithet of "High Priest" and is the current commander of the Royal Guard, a special unit of Soul Reapers tasked with protecting the Soul King and royal family. Ichibei has a range of ridiculously strong abilities, as well as at least a millennium of fighting experience. Ichibei's Zanpakuto releases ink. Anything that ink covers lose its name and anything without a name loses its power. In his Bankai, Ichibe's ability gets even stronger. He gains the ability to assign names to anything he wants by writing Kanji on his target. Ichibe used this power against Yhwach and temporarily made him as weak as an ant.
3 GERARD VALKYRIE
Gerard Valkyrie was a part of the Quincy elite forces, known as the Sternritter, where he served as one of Yhwach's personal protective guards. For most of the Thousand-Year Blood War arc, Gerard faced off against the combined force of Byakuya, Kenpachi and Toshiro's Bankai.
He was only killed due to Yhwach taking back the powers he had given to his Sternritter. His ability as the "Miracle" allowed him to make miracles manifest whenever he's in danger. This ability makes him nigh unkillable in most circumstances, because every time you hurt him, he becomes stronger.
2 GENRYUSAI YAMAMUTO
Yamamoto ruled over the Soul Society for over a thousand years and not once did a single Soul Reaper ever threatened to knock him off his perch. His dedication to training and his strong spirit has made his Bankai a weapon of mass destruction. He has repelled numerous invaders from the Soul Society and even claimed victory over Yhwach, the son of the Soul King. Yamamoto is an expert in the Shinigami techniques of Shinpo, Kido, and Hakuda. This, in combination with his experience and Zanpakuto, means most opponents are left trembling in fear, even before Yamamoto attempts to incinerate them.
A thousand years ago, the Soul King's son, Yhwach, was sealed away for 999 years. Legend says he would regain his pulse after 900 years, his intellect would return after a further 9o, his power 9 years after that and, in 9 days, he would take back the world. This turned out to be more than a folktale, a true to life retelling of Yhwach's backstory. After returning, the Quincy King reignited his war with the Soul Society. Yhwach has a host of nigh undefeatable abilities, inclusive of m future manipulation, enhanced durability and an insane healing factor, to name just a few. In the final war arc, Yhwach came up with a plan to defeat Yamamoto using his subordinates, highlighting the fact that Yhwach has considerable brains to go along with his brawn.