Currently two titans are facing each other in mortal combat outside Karakura town, that due to certain reasons is now located in Soul Society.
The names of those individuals are Ichigo Kurosaki and Sōsuke Aizen.
One of them has the appearance of a human, while the other has the appearance of a monster. Like in most stories, the human is the hero, while the monster is the villain.
The human is known as substitute shinigami Ichigo Kurosaki. Ichigo is a young man that has shoulder-length orange hair and brown eyes. The reason why he is fighting against this monster is in order to save the lives of the people in Karakura town.
The monster is known as the former shinigami captain Sōsuke Aizen. Aizen is a man who has given up his original human appearance in his quest for power and now looks like a butterfly monster with multiple wings. The reason why he is fighting against a human is due to him wishing to become the new Soul King. In order to do that, he needs to create the Ōken which can only be made by sacrificing 100,000 souls in the Jūreichi, that happens to be Karakura town.
So, with both of them having valid reasons for fighting, the fierce battle continues.
As Ichigo blocks Aizen's sword with his own, he suddenly puts some distance between them and starts to build up massive amount of spiritual energy. Aizen decides to not interfere and looks on with interest as Ichigo prepares for whatever technique he is about to unleash.
During the fight Ichigo came to understand that the only way to defeat Aizen is to use the Final Getsuga Tenshō. Tensa Zangetsu has told him that even he does not know what this technique will do to him, neither does he know whether Ichigo will live. He only knows that whatever this technique is, it will be immensely powerful and dangerous. Before he taught him the Final Getsuga Tenshō, he told him about his unique heritage. He told him about his quincy and hollow powers and that he has had them since birth. Those powers are the complete opposite of each other, with quincy powers being considered as holy despite being tainted and hollow powers being considered as demonic due to hollows being beings born from negative emotions.
As Ichigo Kurosaki has finished emitting smoky black Reiatsu and Aizen gets a good look at his new form, he is shocked.
Ichigo now has black hair instead of his usual orange and his eye color is red instead of brown.
'Why did his hair and eye color suddenly change?' thinks Aizen before focusing his thoughts to an even more important fact 'No, that is not important right now. What really matters is the energy he had emitted moments ago. I could not sense anything coming from him, but I could clearly see his Reiatsu.' only to realize 'Don't tell me... is he on a dimension even higher than myself?'
"Aizen, it is time to end this." says Ichigo, interrupting his thoughts, while gathering black flame like energy to his right hand.
"Don't go believing you can defeat me, human!" shouts an enraged Aizen, while charging his own attack.
They then yell out their respective attacks which are Mugetsu for Ichigo and Fragor for Aizen.
As the two attacks collide with each other and fight for dominance, Ichigo's Mugetsu finally overpowers Aizen's Fragor and hits Aizen head on, erasing him from existence, while only leaving a bluish-purple orb known as the Hōgyoku, that is shining with faint purple light.
Ichigo then walks over to the small object which he now decides to refer to as 'the Marble of Doom' and picks it up.
As he holds it in his hands, Kisuke Urahara arrives at the battlefield.
While Ichigo's attention is focused elsewhere, the orb shines a black color for a single moment before completely losing all of its light.
After Kisuke sees no sign of Aizen, assuming he is dead, he finally turns his attention to the orb in Ichigo's hands and asks him to hand it over:
"Can you give me the Hōgyoku."
"Sure." replies Ichigo without showing any hesitation and gives him the Hōgyoku.
Kisuke then examines the Hōgyoku and asks him:
"Has the Hōgyoku been acting strange lately?"
"Not that I am aware of."
"Are you sure about that?" was Kisuke's confused response while adding "No unusual reaction after Aizen was destroyed?"
"Well it was glowing with purple light just moments ago, but now it has lost all of its light."
"I see." was Kisuke's response while thinking 'I may just be overthinking things. Most likely the Hōgyoku has lost its power and nothing else.'
"So," asks Ichigo "does this mean the Winter War is finally over?"
"Yes."
"That's good..." was Ichigo's response before completely losing consciousness.
"Ichigo!" shouts Kisuke while panicking and thinking 'What have you done now?'