The days spent in prison are always dull, even painful.
Daily repetitive labor, guards who enjoy beating prisoners, and even casually chatting with fellow inmates could be monitored—though none of these occur in Azkaban. The inmates there don't need to work, no guards come rushing in to punch you in the stomach, and you can speak freely with your cellmates—
Of course, provided you still have some spirit left.
It's well known that Dementors clearly don't understand human language—or maybe they understand and just don't care.
So in Azkaban, you can do anything you want and are able to, such as—learning how to repair toilets, or even developing a cult.
Obviously, no wizard would learn the former, but Gilderoy Lockhart discovered that someone had been working on the latter for some time.
At first, when he heard he was sentenced to thirty years in Azkaban, Lockhart's immediate reaction was mild relief; he originally thought he might get a Dementor's kiss or life imprisonment in Azkaban—thirty years was ridiculously long, but to say it was short... well, not really short, but it wasn't entirely hopeless.
The year he was imprisoned, he was twenty-nine, thirty years later, he'd be nearly sixty—that's not particularly old for a wizard.
Haven't you heard? Even a 110-year-old man can be called the world's strongest White Wizard, and a certain examiner who supervised his ultimate wizarding exams is still working—it's just that the Magic Realm doesn't seem to enforce mandatory retirement at a certain age; as long as you think you won't die doing so, you can keep working yourself to death—
Thirty years later, he'd be released, and by then no one would remember him; although he couldn't continue to write books under the Lockhart name, he'd retrieve the money hidden in his Gringotts vault, write some money-making stories, and redevelop his shampoo company...
Even before entering prison, Lockhart had meticulously planned his post-release activities—
He had thought these thirty years would be tough, but... never anticipated they'd be this damned difficult!
Under the influence of Dementors, Lockhart's mental journey over the past two years looped from wanting to die → trying clay pottery → finding it utterly uninspiring → regretting → collapsing → wanting to bawl → losing even the strength to cry → continuing to want to die... in endless cycles.
If these thirty years were to be spent like this, Lockhart thought, there would perhaps be a day among those ten thousand when he'd inexplicably gather the strength and decisively use clay pottery—since he wasn't like the madwoman in the corridor next door, who would chant the Death Eaters' action manifesto every morning to cheer herself up...
Her wailing was punctual like an alarm clock... though Lockhart didn't really know how long he'd been in Azkaban or when the sun would rise, that's how he felt—until he suddenly discovered that starting from a certain day three months ago, he'd no longer heard the wailing of that woman.
Of course, it's not because he went deaf, but because that group had started to howl together every morning—
The scene was like a sea of people, loud drums, and fireworks...
It even made Lockhart feel he wasn't locked up in Azkaban but caught and thrown into a Muggle fraud syndicate's base—though this wizard didn't know what a Muggle fraud base was like, that's how he felt—and then, even stranger things happened.
Those Dementors disappeared.
Well, they didn't completely disappear, but they stopped appearing frequently in his sight. Those Dementors that used to pass through the corridor daily vanished, replaced by those brainwashed cult followers—or, should we say—Death Eaters.
Yes, now Lockhart knows who his boss is, Voldemort—a racist ready for a comeback.
Lockhart was initially terrified because he knew he wasn't a Pure-Blood Wizard; his mother was a wizard, but his father was a Muggle, and although he broke ties with that Muggle electrician after graduating from Hogwarts, as an experienced wizard of the first Wizard War, Lockhart knew well how cruel the Death Eaters could be—
Though it's from reading the Prophet Daily, it's the most reliable information source a normal wizard could access.
Otherwise, what should they trust? The Quibbler?
But, as stated in the earlier part—yes, now Lockhart also became a Death Eater—even though he had no organizational identity and failed to memorize the entire Death Eaters action manifesto after nearly two months, Lockhart is still a Death Eater—or rather, everyone in Azkaban has become a Death Eater.
Those who ended up here weren't exactly good people, and everyone from top to bottom embraced the family of Death Eaters, becoming "an intertwined family."
Though Lockhart heard the guy in the cell next to him mention several times that he missed two familiar faces in this "family," no one really cared. The Dementors, while adhering to their agreement with the Ministry of Magic by not intentionally harming these prisoners' lives, always had some unlucky with poor health—
So their new boss—though this boss demanded to be called master with some SM-related quirks—wasn't bad, at least he wasn't like the Dark Lord's rumored ways of shouting and killing at his subordinates, nor did he randomly grab someone every day to torture for power, but Lockhart was still very afraid—
Even though he insisted his parents were both wizards, that he was a wizard from the Prewett Family lineage, tracing back eight generations with roots in England's Wizarding World as an old pure flag, maybe his ancestors had served as Imperial Mage, Lockhart was initially very scared of being exposed—
Fortunately, Voldemort didn't seem to care much whether his subordinates were Pure-Blood; he appeared desperate for manpower, expanding the Death Eaters army without discernment.
If, if Lockhart's mind hadn't been tormented by Dementors for these two years, with his intelligence he could have figured out—
Voldemort needed manpower → he gathered tons of fresh blood as Death Eaters → Voldemort intended to stir things up →... were these people caught as "fillers"?
But alas, the world lacks "ifs."