Riku's POV. 100 years in prison.

Slowly opening my eyes, I see the same dull grey cell walls I've seen for the last century. Releasing a sigh, I call out to my zanpakutō, 'Morning bud, anything changes while I was asleep?' Hearing his deep hum, I could tell by his tone that his response was negative.

One good thing about being trapped here with him is that I have grown much closer to Sōten ni zase than I think I would of, even after centuries in the outside world. If previously I could only guess the meanings of his hums, now I can fully grasp the ideas he wants to communicate as well as the tone he wants those ideas communicated in.

And it turns out that he loves deadpan jokes and puns, a preference that is not mutual. Even though, in a metaphorical sense, zanpakutō are meant to be the truest reflection of a Shingami's soul, I refuse to believe I'm a boomer at heart.

Shifting the focus to my surroundings, I begin my daily routine. Firstly, the seals.

The energy flow seemed fine, with no irregularities, which was a recurring problem a few decades ago. Although I had done a good job constructing the seal, considering my lack of prior knowledge, the problems that came with a lack of formal training started popping up.

Things like inefficiencies in the seal matrix that aren't apparent at first or random energy paths that slip into the final product and make the seal consume more reishi than is necessary. All in all, the seals became a welcome distraction. Regularly trying to optimise it only to find out that the optimization introduced an inefficiency elsewhere, so you have to start the cycle again became my favourite pass time.

Moving on to the next item on the list, the projects.

I couldn't substantially improve them after all this time. The spell matrices had been optimised to their limits. All I could do was add additional features. The most important add-on I introduced over the years was a way to hide the effects of the spells.

I added a concealment matrix to each spell so that even the most sensitive individual wouldn't be able to tell the spell matrix apart from my natural body. So the near-constant stream of reishi flowing into me will seem no different than the 'cultivation' of a Shinigami.

Clenching my right hand, I couldn't help but grin. The bodily strength I now had was off the charts for a Shinigami. Although I doubt I'm anywhere near Zaraki in his Bankai form; I dare any Vasto Lorde to step in the ring with me.

According to my estimates, I could bulldoze straight through a hill and only receive a few scratches. Ironically, my fighting style does not require me to have my current level of physicality. But reducing my number of weaknesses is always great.

My reiryoku growth has been my main area of improvement over the decades. Although the amount of reishi available to me is not even slightly comparable to what is readily available in the Seireitei, around twenty years ago, the amount of reiatsu I could exert was significantly higher than what Isshin Shiba could in his Shikai state.

He probably improved over the years since he was a relatively young Captain with great potential, but the point still stands. Now, however, I have exactly eighty-two per cent more actualizable reiatsu than what I remember Isshin emitting.

Meaning I've silently stepped into the big leagues. I would still get curb stomped by Yamamoto or Unohana, but they have reached their peaks, and I'm still growing. Sooner or later, I'll be able to look that man in the face and not flinch.

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And finally, I started checking the reishi stream flowing into my cell.

I've been steadily increasing the thickness of the stream over the years. A few years after I had undone the original seals, I encountered a bottleneck in the proficiency of my reishi control.

The roadblock had come quite suddenly as well. I had tried multiple ways to overcome the bottleneck, but all methods failed spectacularly. My leading hypothesis for this sudden bottleneck was that I just did not have an in-depth understanding of the different 'flavours' of reishi. For instance, I have never come into contact with Quincy-tainted reishi, not to mention sitting down and slowly studying it.

That lack of perspective is likely hindering my exploration of the 'true' form of reishi. So instead of stubbornly insisting on training my sensitivity, I started seriously training to expand my sphere of influence. The training itself turned out not to be particularly difficult.

However, my range was not progressing at a satisfactory rate due to me having to be extremely cautious with how I release my reiatsu into the surroundings outside my cell. The entire prison, from what I could tell, was crammed with seals, with these seals interlocking with each other in such a way that undoing one seal would immediately give feedback to the other seals, presumably alerting the Detention Unit.

Some of these annoying seals could detect reiatsu if that reiatsu was at high enough concentrations. Luckily I could study the seal's structure by inserting tiny amounts of my own reiatsu into them, but it also meant that releasing enough reiatsu to control reishi far from my cell became practically impossible.

But if there is anything I've learnt in this god-forsaken place, it is patience. Gone is the rowdy youth that burned with righteous indignation. In his place now stands a tempered man. However much I loathe the Gotei 13, I've come to peace with my situation.

I had been living life with the arrogant assumption that excellence would be recognised and respected. My time in this place allowed me to correct that notion. This world is inherently shitty, and I was finally able to understand that. Instead of fury and fire, one needs a detached pragmatism to survive and, more importantly, to thrive.

In hindsight, my actions as a Seated Officer were reckless and short-sighted. I was contributing to an organisation that I knew gave zero fucks about me. I was a dog on a leash that they could get rid of at any time they so pleased. And the real tragedy? I offered up myself to them on a silver platter.

Every benefit being an officer of the Gotei 13 provided, I could have obtained by myself if I had been patient and wiser. Kidō, for instance, is readily available to nobles. Doing mercenary work for nobles or stealing from them could have resulted in me easily obtaining Kidō numbered sixty or below. Asauchi as well, are not rare outside the Seireitei either...

Picking up an incoming reiatsu signal, I slowly started getting up from my meditative poise. Giving the cell that has been the physical embodiment of my despair for the last century an emotional once over, I started running my fingers over the blood-stained tears in the wall. Each scratch represented a moment in my life when I allowed hatred and sorrow to win. Each scratch stood as a testament to how successful this place was in its mission. I knew this place broke me. I now just have to move on and attempt to fix what I can.

Hearing my name being called out after so many years was enough to take me out of my reminiscing. "Former Third Seat of the Tenth division Riku, by order of the honourable Central 46, you have been deemed to have served your complete sentence. You are to cooperate with the Detention Unit as we escort you off the premise."

Withdrawing my hand, I finally turned to the reiatsu signal outside my cell door. Speaking to me was a thoroughly uninteresting Shinigami wearing a spin-off of the Second division uniform. He hadn't opened my cell yet, likely waiting for his reinforcements before he proceeded to release a potentially dangerous individual.

Although he didn't know that he was not actually safe behind his jail bars, I decided to play along. While I waited on his friends, I started to stretch out my limbs in what seemed like years. Seeing me fully rise allowed him to fully take in my now large stature, which resulted in him quickly taking a step back.

Before my imprisonment, I was a 1.70-meter kid with slightly above-average muscle mass. However, my mental state is not all that changed over the years. After so much time, my strengthening spell has transformed me into a two-meter-tall Greek demigod. My unkempt hair and beard likely didn't help, either.

Letting the conversation lapse into silence, I ignored him and started going over my future plans. 'Before anything though-' I thought as I ran my hand through my dirty hair, '-I need a shower...'