I just read these first four chapters in quick succession and conclude that you have a very promising start to your story here. I would like to acknowledge a few things I think you did well in the hope that you'll continue doing them as this story develops.

First off: You write very well, which certainly isn't a given on this site. And I don't only mean that grammatically and structurally everything is correct (the first hurdle that many do not clear), but rather that your writing style is pleasant to read and that you manage to keep a reader's interest throughout the chapter. You don't ramble on about certain details, you don't repeat the same phrases over and over again, your descriptions of scenes are interesting and you show the reader what he needs to know rather than explaining it to them which is a common, but damning mistake many first time authors make. I've seen it often that authors give in depth analyses of a character's feelings at any given time when a brief description of their body language or face would have sufficed. Explanations make a psychologist's heart beat faster, not a reader's. So good work on avoiding that.

2: Your characters are well rounded and their interactions are interesting and natural. You're using a somewhat 'standard' cast to begin with but you've written them in a way that corresponds close enough to their canon or fanon characterizations. Up until now your only 'OC' is Auror Proudfoot who has taken on a mentor role reminiscent of Mad-Eye Moody. As the story develops I hope that this currently small circle of characters would gain more novel OCs.

3: Your description of magic in this fic is very well done. In the instances that you do introduce 'magical theory' you do it in a way which is relevant to the plot. Many authors introduce 'training montages' à la Rocky that only serve to illustrate how powerful and knowledgeable the protagonist is.
Every time you explain how a bit of magic works you use it later on in a way that directly impacts the plot. Harry's intensive training in transfiguration is what saves him in his fight. It also helps that you have given the magic a novel twist in your fic (the explanation as to why you need to speak spells was quite novel and intriguing. I wouldn't be surprised if a few aspiring authors will copy that in future...).

4: This point can be seen as an extension of the last (or rather the last point can be seen as an extension of this one the border between the two is rather fluid).
You have adopted a good mix of established ideas and novel ones of your own. Case in point being the use of transfiguration in combat. While the idea has been around for a while you have expanded on it in a more detailed and somewhat theoretical manner which has been a joy to read. You have chosen apt names for your 'new' spells and manoeuvres and your transfiguration exercise was intriguing. I also enjoyed the brief historical account on the development of the Aurors and Unspeakables which gave an additional 'sneak peek' on the history of Magical Britain. It was a nice little detail to add.
Another such idea is your version of the Order of the Phoenix. I'm very curious to see where that rabbit hole will lead us to. And last but not least is the cheeky little cliffhanger you've given us with the whole Dumbledore/Grindelwald development. I've never read a 'Grindelwald in Dumbledore's clothing' fic before (which I hope this is) and am looking forward to seeing how you'll play this...
All in all you've done a good job of keeping your cards close to your chest and revealing them one at a time.

The one thing I was a bit disappointed about was the clash between Harry and Daphne in this chapter. I understand both character's motivations (and agree with them) and can see why you wanted them to clash over this at some point, but I wasn't satisfied with how you did it.
There was very little indication beforehand that a conflict was brewing and it happened far to abruptly to be natural. They went from zero to a hundred within a split second (Harry's Death Eater remark and the ensuing slap) and then cooled off just as quickly. It didn't seem to correspond with either Harry's notorious stubborn streak or Daphne's pride. It felt like it was a bit of a chore that you had to get through quickly so that you could get back on track with the story.
Next time I would have a bit of a slower build up to the whole thing. As I mentioned before, this certainly is an issue that H & D would clash over at some point, I agree with you there, it was just your 'modus operandi' in this instance that was off.

In conclusion: Good job up until know and congratulations on a promising start to your story! I'm looking forward to the next installment!

Incredible! I love the explanations of magic, I love that your Harry has to work for it, I love the angle of Daphne as his second wand and healer!

This is good. Really good. You have to keep going.

I think this story is off to a great start.

Harry is a bit more angsty and broody than I would like, but I realize that survivor's guilt is a thing, and as long as it doesn't big the story down, it will be fine.

I also noticed that Harry scratches the nape of his neck a lot. If that's supposed to somehow be foreshadowing, maybe connected to Daphne healing his throat, than that's great, and you're probably drawing the right amount of attention to it. If not, and it's just a normal nervous tic, then you might want to consider rephrasing it sometimes. While there's nothing wrong with saying "the nape of his neck," it's just unusual enough to stand out. If you're trying to draw attention to it, that's great, but if not, adding some variety to how you describe the action would probably make it stand out less. (You did mention him scratching "the back of his head" once this chapter, and that barely registered for me, but I noticed each of the four times you mentioned his nape.)

Anyway, tiny complaints aside, this story is great, and I look forward to reading more.

Daaaaaamn son!

Harry is a whiny fck please change that aspect of him, in Cannon he let death of Sirius Black go without being moody moron why change that aspect of him just for some angst.
Rest of the story is good except the Daphne joining him is little forced but pairings are pairings.
Looking forward to what else you'll change in wizarding mythos

Something forgot.

"tears" appear 2x in chapter.
Regarding section where they're Harry's:
While more difficult to write.
A less simplistic than "my fault my fault...if only I'd been more BAMF...", cry cry, boo hoo hero, is better IMO.

Now. A lot of fics here are popular, readers lapping up the "realistic" amateur builds of uber angst stuffed emotional wreck (crying jag Harry even common) psychologically damaged emo Harry character builds.

A less simplistic, inline with say survivor's guilt.
A more subtle less black and white explicit portrayal of "guilt ridden" selfless self sacrificing Harry, while more difficult to write, a more subtle realistic more complex a portrayal. And a better story?

The fight...with the too common slap the boy action:
Seemed rushed, maybe more drawn out buildup, argument heating up, might make it seem less rushed, the slap sudden & maybe OTP.

Astoria said: Dammit. Why why why, with fanfiction folding, spindling, mutilating canon. Not too mention all that slash & mpreg, Snarry, Tomarry, Drarry, and AU, Dramione. Why why why dammit aren't I allowed a pardon from JKR cursing me twice. An effing blood curse, and worse, marrying that sack of irredeemable shit, Draco? Why do fanfic writers hardly ever deviate from ruining my life, running it on canon rails?

Great story, keep updating. Cheers!

after major assessment (not even mentioning the minor ones) every week ... Apparently studying in med school is not conducive to creative writing, who would have thought?

Med school?
Bio says USA. So no need to ponder about "med" in UK or elsewhere encompassing veterinary medicine.

Hmm, nope, next line wasn't waking up in some animagus form.

So Harry with a "FORELEG?"
Humans have forelimbs maybe?
Is leg below the knee, thigh above, maybe upper and lower leg common vernacular, but not medical terminology?

Rhetorical questions, just thinking out loud. Not asking for reply.

Some good innovative colorful writing.

Eg. Kingsley's smile: features into a sheepish smile, but something about it reminded Harry of a rotten core in a seemingly fresh apple.

That's certainly not a cliché "?simile?".

This story has a lot of promise. As such, I can't recommend enough that you go over to Dark Lord Potter (DLP) and go to work by author for advice. Even the best authors of fanfiction use the advice they get to improve their stories. For example, they might offer some advice such as switching "combat and detect" in chapter 1 to "detect and combat". They'll help you edit (no need to search for an editor), help you understand how a reader views the fic, help you with the plot, etc.

A bit weird that Harry still calls Molly and Arthur Mr. or Mrs and I've also found it weird that Hermione resorts to casual violence like hexes with her wand against Harry/Ron. Imagine you exchange magic with fists and that is what pretty much happened. There only goes so much good-natured fun.

ohhh you know how to end these chapters alright.
that was really good

Hello! I have to say I'm veery happy that I was wrong in terms of this fic's abandonment. The plot just seems to get better and better! I also like the Daphne Harry banter a lot, it is definitely one of the most enjoyable ones on the site. Thanks for sharing and upate soon!