(Note: The way I wanted to go about this wasn't available but this option was the closest. Also note that in this storyline not a single female character from the Harry Potter world died. Yeah, its weird like that but only men croaked in the War)
Harry Potter sat in the recliner, watching as the fire crackled in the giant fireplace. His fingers idly drummed against the armrest as he thought over everything that had happened over the last few days and what it meant for him.
Voldemort was dead. Finally, after over 7 years since he'd first entered the Wizarding World, the snake-faced bastard was dead. No coming back from this battle... Harry had seen to that. Of course, as with many things in his life, he hadn't been able to achieve victory without some people being pissed off... namely many of the wizards in Britain. Voldemort, being a petty little bastard, had tried to attack Harry with one final spell as he went down... something about wiping out the Potter bloodline or some rubbish like that. Harry had managed to throw up a shield spell when Voldemort had cast his final spell and the end result had seen the curse splintered and striking half the wizards in Great Britain. Suddenly more than 50% of wizards found themselves unable to get their... wands... up. Harry, upon hearing the first cries of panic and outrage, had wisely decided to hide in the Room of Requirement until it all blew over. Thanks to the House Elves Harry had been able to enjoy his two weeks of solitude in peace.
During that time he had reflected on his life and everything that had happened and come to a decision: it was time for him to finally get what he wanted.
And Harry... wanted to get fat.
If he had talked about this with a psychologist the shrink would theorize that Harry's early years are what had caused him to become fixated on packing on the pounds. It wasn't just his lack of food that made him now want more of it; no, it was how his mind equated weight and power. His Uncle Vernon was a huge man and was a commanding, powerful male. So too was his cousin Dudley. It had been imprinted on Harry since he was a child that fat=power. Hagrid had only strengthened this view. The half-giant wasn't a tub of blubber but he was heavy set while being quite strong and having a connection to the world of magic. That had sealed the deal for the boy that was just nearing puberty and for the last 7 years all Harry had dreamed about was packing on the pounds himself.
He chuckled as he watched the fire. His professors always complained that he seemed to have not inherited his mother or father's intelligence. What they didn't realize was that Harry had... he just focused on one specific category: weight gain. He'd spent years learning every spell, curse, rune, enchantment and potion that could bloat up a body to the perfect size. He wondered what Snape would have thought had he known that by second year Harry was brewing fat-creating spells that were considered difficult for Potion Masters.
The only reason he hadn't engaged in his plans was Voldemort... and not for the reason anyone would think. In Harry's mind, if he gave in to his deepest desires he'd be letting Voldemort know of the power that came from being huge and fat and the Dark Lord would do the same, packing on the pounds to challenge him. Harry couldn't have that... no, not at all.
The young man took a moment to envision his ideal self. He saw himself being at least four times bigger than his uncle, wonderfully bloated with a massive stomach that draped over his thick thighs with only his fat cock managing to stick out. He could see the heavy man boobs that would protrude from his chest, his flabby face with its many chins, and his monstrous rear that would crush anything he sat on.
But the dream of his true self, the one he'd had for so long, had changed when he reached puberty. He still fantasizes about being fat but now he wasn't alone.
Harry wanted a big beautiful wife to grow plump along with him.
Every night, when he went to bed, a different girl or woman would appear. He'd dream of himself and one of his friends, or a member of the Order, or a classmate, or even Death Eater females surrendering themselves to the joys of fat. They would swell and gorge together, her massive belly rubbing against his as they got bigger and bigger and bigger...
Harry shook himself. It would no good to fantasize now... not when he could finally achieve the real thing.
Yes, he had decided that today was the day. He would select the woman that would grow with him and they would begin their journey towards becoming glorious gods of gluttony. He had spells and potions and other means ready to begin the process... and to help break his choice should she be unwilling at first to embrace the new life he was giving her.
Harry smiled as he focused, commanding the Room of Requirement to send him his woman.