Alright, so for this fight i would reccomend some armor that you can at least not fat roll in, a weapon that you can buff with Gold Pine Resin or Bundles, TONS of Gold Pine Resin and Bundles, and, most importantly, NO SHIELD. Yeah, we're going full Bloodborne with this ♥♥♥♥.

To put it bluntly, in this fight Shields, or more accurately blocking in general is a TRAP. Yes, that +10 Curse Ward Greatshield has helped you immesely good friend, but here? Here it's DEAD WEIGHT. ALL of Darkeater Midir's attacks wear down your Stamina far too heavily for blocking to be effective, the moment a hit grazes that stone bowl which you put your faith in to protect you is the moment it gets used as a platter to serve your dismembered torso to an immortal being whose mind is consumed by the abyss which he faught, and while he acts faster than most bosses and deals insane damage, being able to two-shot most people with ease, the fact that he's bigger than most makes the time it takes for those hits to actually land perfect for jumping between his back legs and chopping away at his toenails until his feet are a fine mist.

Alright, now that we know the basic equipment we need and the fact that one of the methods of avoiding getting murdered is such an effective trap that you'll be a fine mist when it's done with you we can get on to his most dangerous attacks, and here's where what you've learned so far comes in handy. Yes, his claws are dangerous, if you carelessly run in you'll essentially have just willingy shoved your face into a meat grinder, i'm not denying that, however, his most dangerous attacks all either come after that meat grinder or instead of it, and these are also the attacks that are the main reason you're not relying on your oh so hallowed "NOT-THE-FACE" buttons.

The first that we'll talk about starts out looking rather dumb, he starts breathing fire at the ground for a second, keeping you away effecively enough, but that's only the wind-up to the real uppercut to the nuts, because after that second of fire it condenses and converges INTO A MOTHER-♥♥♥♥♥♥♥ DARKNESS LASER! Yes, they gave the dragon that eats the abyss darkness laser breath, and yes, you should be scared when it rakes that laser across the ground, and yeah, the ground explodes less than a second after, but it won't hit under and behind him.

The second, well it's just regular fire breath in a straight line... yeah, kinda average but still EXTREMELY dangerous. He may also follow it up by breathing fire from left to right (left from the front) and this, while not AS dangerous due to the motion making it so you aren't stuck in it for most of it if you're hit, but it's still better to be careful as it still hurts.

Next, two claw swipes before rearing up and breathing fire straight down. The safe move with this attack is to run away in front of him, because it doesn't reach too far in front of him, but if you're feeling cheeky you can dodge behind him rapidly and try to get a few swings in on his tail while he's stuck in the fire breathing animation. be careful, as it actually reaches futher behind him than in front.

For the first phase Midir's charge is relatively easy to avoid, just dodge towards him when he's about to hit you and you have a prime oppurtunity to wail on his ankles, in the second phase it's a bit more complicated... well, not that much more complicated, he does a second charge once he finishes his first and turns around now, but still.

These final ones are what you really should watch out for. First, we have an attack in which Midir charges up for a powerful AOE blast, you might be tempted to get in a hit while he's charging before running away, this is a bad idea and you should feel bad. When he starts the windup for this run immediatly, you'll ALWAYS die near instantly.

Next is a giant laser, he starts out firing forward, but then he starts flailing his head, hitting almost EVERYWHERE. Again, it won't hit under or behind, but getting close enough is EXTREMELY challenging due to the sheer amount of coverage this gives him.

Finally, he has an attack in which he charges up for a second before calling humanity sprites similar to the Affinity Sorcery, he calls out a large amount of them and they all go after one person, so this can quickly take out those who are unprepared, but if you dodge to the left or right quickly and repeatedly you can avoid them completely, but Midir may attack before they're all gone, which can complicate things.

Alright, now time for one last piece of advice before the conclusion, having more than one phantom makes all of them die in one hit. There, done. I've given you all the advice you should need to Git Gud and fight a corrupted archdragon. good luck guys, you'll need it.