Grimmjow had a lot of scars.
Not all of them were visible, though some were. But there were a lot of them. And each one that meant something held a story behind it. A story he would never forget.
There was the scar on his back, long since vanished when he became an arrancar, but the memory of it would never fade. The memory of his first fight upon becoming an adjuchas, a fight he barely escaped from. A reminder to never underestimate an opponent, never think he was completely safe. It was a reminder he forgot from time to time, but the collection of scars served as an increasing reminder.
Then the scar on his neck, right below his mask. Hard to see, but there. He knew it was. It ached sometimes, especially after a rough night of forgotten dreams. Self-inflicted, right after he gained human form and became an arrancar. A panicked awakening, clawing at his mask as if to rip it off. The scar served as a reminder of what he was, and sometimes of what he used to be. He tried to ignore it most of the time.
There was a scar on his leg, his knee to be precise. A reminder of Aizen's power and capabilities. He'd gotten it the first time he'd spoken out, spoken back. Aizen had done what he'd always done since, pushed him to his knees, dragging him to the hard, cold, floor - humiliating him. It was another ignored reminder, but one that always served to anger him.
And there were the scars that were invisible, thanks to the healing princess. Where his tattoo was, and sealing his arm together. Reminders that he could be defeated, could be harmed, could be broken and humbled. Those reminders hurt. They may not be marked on his body, but they were marked on his spirit.
Of course one could never forget the scar that was his pride, his anger, his obsession and his everything. The scar Kurosaki Ichigo gave him, proud and strong and always visible under his opened jacket. That scar that prey gave to predator, that he kept to remind him of the first purpose he'd been given as an arrancar, his first real reason to fight. He still kept it, even now, as a reminder that even he could have things to fight for, even if they were selfish and cruel.
And finally, the newest in his collection, the scar on his shoulder, making his arm ache and move slower then it should. It had healed, but it left it's mark, both on skin and spirit. It had brought him too close to death, too close to the end. It was a reminder of mortality in death, and his fear of it.
None of them he would ever get rid of, no matter the pain they caused him. They were part of him, part of his experiences.
They were his story.