Well Rukia is going to be pissed now that's for sure...
In a situation like this I would sic Byakuya on Dumbridge... Hehehe *evil grin*

OHHHHH! CEDRIC, CEDRIC, CEDRIC!

Well shit... Dumbridge just arrived... May Kami help us all!

*starts singing* I think I love youuuuu! Damn this story is fantastic!

I'm enjoying this so far, but you could really do with a Brit-picker. You've made quite a few mistakes when it comes to English terminology. Most of them are quite small (you've got a few Moms instead of Mums, we don't have Pepto-Bismol, and some others that I'd catch if I saw them again), but the big one is in this chapter. In the UK curriculum, we don't learn about the American War of Independence. All the info I know on it is from the internet. It's also unlikely that Ichigo would have learnt about it in school. So maybe you should have used another reference?

Everything else about the story so far is excellent. Your spelling and grammar is mostly perfect, and your characterisations are spot on. I'll continue reading :)

Let's see. This is not bad, per say. I've read both this story and the sequel, so let me start from this story and you should be expecting another review coming soon enough on the sequel.
First of all, for the sake of my sanity, let me list the pros and cons of this story - starting with the cons and for this I'll go straight from the beginning.
1. Okay, WTF? Since when was Aizen able to open a Garganta? I was under impression that THAT particular ability is limited to Hollows and Arrancar... and he's neither. Sure, works with the purpose of the story, but it is one very, very, VERY improbable thing to happen. Which brings me to point number 2.
2. Aizen would NOT run away. He'd trick Ichigo, do something else equally insane or just plainly feed on Hogyoku's power, as shown in canon. It works with the purpose of the plot and all that, but it counts as a majorly OOC moment for both Aizen and later on, Ichigo. Which brings to point number 3.
3. Err... Ichigo never converted his Reiatsu into his physical power, as stated in your chapter number one. That was only Aizen's impression of it. (This is said in the very... what 3rd, 4th paragraph of the story? If you've edited it later on, I'm really not sure so if you have, ignore this). He literally grew so much stronger that NOBODY could feel his Reiatsu. Which is a big failure of this story as a quality work because Kubo then created an overpowered hybrid and needed to settle that (Mayuri's rambling about perfection, remember?) There's no room to grow anymore. Magic's not an adequate solution for that. But oh well. It makes the story somewhat interesting. Up till we come to the point where Ichigo effectively sealed his Shikai. Umm... constant release type ringing any bells? But all that aside, I moved on. This was started ages ago and perhaps not all the facts were known, so all right.
4. IchiRuki. No. Before you think that, no, I'm not IchiHime fan. Actually, I favor IchiRuki so much more that it hurts. My problem with this is... OOC. VERY, VERY MUCH SO. While your character interactions were always on the plus side in my opinion (I'll get to that later), what you've done here is literally making them into a freshly formed Shoujo couple. Which SUCKS. Rukia's birthday, the whole we're now together manner and all that. The big problem comes from the fact that if we know anything about Ichigo's character. Sure it's fanfiction and all that, but I'm not flaming... not really. Just pointing out some facts. So Ichigo may or may not love Rukia in canon, that's up for debate at any time, but your interpretation of his 'realization' can be summed up in: 'whoa, hey, I love Rukia. Cool' Not Ichigo at all. Their interactions later on are acceptable, but... well, every little advice Ichigo had given to Harry and others about love in this part (and the next) reeks of Gary Stu because even if he loved Rukia, how the hell would he know everything? He's the type to care wholeheartedly and die for anyone he cared about, not the type to understand how and why he cared about them. Hell, I doubt he's even the type to remember birthdays, holidays and stuff like that. He knows about it all right, but simply doesn't care. Which makes what you've done with them as a couple a mere mockery of IchiRuki... of sorts. And since I can see you're as much of an IchiRuki fan as I am (which is really a lot) I'd suggest you read Notes on a High School Scandal by Jaina. Absolute best IchiRuki story ever that is not AU. It's a good example, really. But otherwise, since your main plot isn't romance, I moved on. As long as there aren't any Shojo elements, they're both pretty much IC which is a great feat in and off itself. Just one other complaint on Rukia's character, and I'm done with IchiRuki, promise. Rukia's possessive? Ignoring the whole Chappy stuff and rabbits involved, HELL NO.
Moving on.
5. Masaki Kurosaki. Knows everything.? Check. Genius? Check. Nearly-worshiped by anyone who has known her? Check. Has absolutely any detail that the plot demands? Check. Descendant of all four founders? Check. Err... that's cliche and unoriginal and completely fits the Mary Sue category. Nothing more to be said on this part.
6. Umm... Kurosaki Isshin... rogue prince of Soul Society, son of Old Man Genocide himself. Well, starting that there were absolutely no indications of this AT ALL in canon... let's just says that sometimes, being original goes too far. And Yamamoto being lenient on Ichigo does not explain it at all. But then again, the fact he's a Shiba came out recently so I guess I can't really say anything... however, this was impossible long before Isshin was a Shiba matter came out.
7. Ichigo's scars... err... what? Fanservice aside, we get Ichigo's bare chest like every other fight he's involved in... umm... if there were any scars, wouldn't we have seen them?
8. Ichigo's talent with magic? Uh... interesting. But it sounds more like you were lazy to write him actually trying to accomplish anything.
9. Ron... err... I think it is evident from your work that no, you do not love his character at all.
10. Ichigo's far too friendly for his character... but oh well, as the plot demands...
11. Err... we've got a whole bunch of new characters added to the Hogwarts mix yet barely anything changes at all?
12. Zangetsu and Ichigo's Hollow's appearance? Well, overdone. Besides, weren't they like, accepted and all that and thus merged? Though one could apply that to reading Hogyoku ex Machina (another amazing story) so I may have not gotten my facts straight. You may ignore this if you like.
13. Character bashing of Umbridge and McLaggen respectively. Um... you may not like them, yeah, but they're CHARACTERS. Write them in a way they're disliked, but at least competent for something.
14. Wands firing Kido Spells and Zanpakuto attacks? Err... I'd rather not make any further comment on that.
15. Power levels. If Ichigo's already a transcended god and all that, even when sealed being knocked out by a couple of strong spells in exactly the same spot sort of makes it unbelievable. It's like you're trying to tell me that throwing a pair of pillows can actually break down a wall. Let alone the possibility of Ichigo ever being hit in the same spot twice. Say, whatever happened to Shunpo? And Ichigo's abilities too? Even without Bankai, he's far too fast to NOT be able to dodge no matter what any wizard threw at him.
Any other con I may have is postponed for reviewing the sequel. I think I've handled most of what I wanted to, anyway.
Before I move on to the pros, I just want to point out that the reason I'm doing this is basically because your work (if we ignore most of the written upstairs) is actually brilliant. This is one of the amazing things because you've got a good grasp of characters, brains and your writing style conveys everything you've got to say in a really amazing way. So no, all the attention this story has is not without its merit.
Now, the pros:
1. As I said, your writing style. The way you paragraph and your choice of words is honestly inspiring and a big, big plus to your writing. Now if you'd just be able to avoid the obvious pitfalls, that'd be utterly brilliant. For now, we rest between acceptable and good.
2. Character interactions. All my compliants aside, you write characters well. They've got their personalities and they are not bland, as in many fics it happens. That is great and it means that even though the result is good, there's still room for improvement which is, in fact, important.
3. Well, we have at least some guarantee that you'll end this story, which is a good thing, because many don't finish their own. This trilogy (well, not yet complete) at least has a great possibility of being complete.
4. This particular thing could be considered both a good and a bad thing, but I'll settle for the good. Relationships, but most of all, Harry/Ginny. There were far too many Shojo elements again, what with blushing and that, but one can ignore that with vigor so it's good. My point is, you've made a more believable relationship between the two of them than J. K. Rowling ever had, and that's really something. You've threw in many hints before actually hooking them up, for a difference of what happened in HBP. You can be proud of yourself for that. Uhh... as for Luna/Ishida... not so much. There I'm starting to feel as if you're just trying to pair up every single more important character, which is... scary.
5. Dumbridge. Moldy. (Again, it could be both good and bad, and in this case it is both). It was interesting in the first, what? 5 chapters since you've started using it? Soon enough you went overboard.
6. Toshiro, Momo, Mizuiro and Tatsuki. I think this is self-explanatory. It's a bit unlikely that Inoue lack magical power when her own powers is Reality Wrapping, but oh well. It is nice to see an IchiRuki story in which she's not outright bashed.
7. Tatsuki/Fred? Did anyone ever tell you just how FREAKIN' AWESOME that is? Yes? Then let me tell you again. IT'S FREAKIN' AWESOME!
8. Snowball fight during the Christmas Holiday? I haven't had that much laugh from reading a snowball fight for AGES. You've got a great sense of humor and talent for executing it. More than I can say for the most.
9. Cedric in Seireitei? Err... I don't know how he got there, but that's AWESOME!
10. Sirius' death? I'm awful, I know, but it's NICE when somebody does a crossover with OotP and in fact he does end up dead instead of miraculously saved by a stranger. Err... I could probably elaborate on this further, but I have a feeling that the more I go on, the less sense it would make.

You know, it's creepy how long this had gotten. Anything else I have to say about this is going to be in the review for the sequel. And I'll get to reviewing that sometime or later, but I will, nonetheless.

nice love the whipped comment

Chapter 8. can't believe Ichigo would whine about little blood loss, or thinking of using a dragon to fight Aizen with. Its really hard to picture since I doubt that a dragon would stand a chance against any of the arrancars let alone the three rogue captains.

It is an interesting fic. But the way you connect the two worlds isn't really getting to me. That's my opinion though.

OPed an OPed character

Yamamoto the closet ichiruki fan XD

I can't stop laughing at that XD
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*still laughing*

I love what you did with this chapter. I love that you brought in Grimm and Nel, and the hints that Yamamoto is actually Ichigo's Grandfather. I really love where you are going with this!

I loved all of this chapter. My favorite moment really had to be the discovery of Isshin's domestic failure. I really don't think he knows how to keep house on his own.

I love that you used the visard. They would be the best at blending in.

Nice wrapping up!