Here are some opinions about a fight between Isshiki and Aizen: I think Isshiki dominates physically—his strength, speed, and chakra control are on another level. He can shrink or banish weapons to another dimension and trap Aizen with chakra rods. If Isshiki lands a hit, Aizen could be seriously restricted or even sealed away. However, Aizen’s greatest strength is his Kyoka Suigetsu (KS) illusion ability, which controls the senses and can completely blind Isshiki’s perception of reality. This makes it very hard for Isshiki to land a clean attack. Aizen also has incredible stamina, immortality, and rapid healing, allowing him to endure even powerful physical hits that would bring down others.
Some say Aizen’s illusions would overwhelm Isshiki, who hasn’t shown a clear way to counter KS. Others think Isshiki’s superior chakra control could break or resist the illusion effects, but that’s uncertain. Aizen’s portals and ability to resummon weapons add versatile options in battle. Overall, Isshiki outclasses Aizen physically, but Aizen’s hax and endurance make the fight very close.
In conclusion, I believe the battle would be intense and evenly matched. Isshiki could overwhelm Aizen quickly with physical power and traps, but Aizen’s illusion mastery and immortality mean he could outlast Isshiki in a prolonged fight. So, while Isshiki might have the upper hand in raw power, Aizen’s endurance and illusions likely give him the edge in the end, making Aizen the probable winner in a drawn-out battle.
