I JUST COULDN'T STAY AWAY

First off, a few addendums to Chapter 4 because I realised I hadn't properly checked all the possibilities for battle 17.

=== BATTLE 17 ===

(Jubei dies before recruitment)

[ADDENDUM 1]
R: This is the second time someone's said 'um' and ruined a dramatic moment.
A: "We were too late...Jubei has been defeated."

[ADDENDUM 2]
R: Awkward clause ordering.
A: "I lost my right eye training myself to the limits of Yagyuu Shinkage, but I still wasn't strong enough to challenge the Rainbloods."

[ADDENDUM 3]
R: The punctuation used here is a bit odd.
A: "Younger brother Muneyoshi, uncle Hyogo...Avenge me! Ugh..."

(Post battle cutscene; Jubei dead)

[ADDENDUM 4]
R: Clunky.
A: "We've truly defeated the Rainbloods? Their strength really is lessened when they are divided."

[ADDENDUM 5]
R: Same problem as 112 in chapter 4 - takes the defeat of the other armies as fact rather than speculation, and lacks the punch final words should have.
A: "Once our fellow Rainbloods have defeated the remaining armies, they will be certain to avenge our defeat! Ugh..."

(Post battle cutscene; Jubei alive but not recruited)

[ADDENDUM 6]
R: Awkwardly worded. Jubei here is admitting to himself that he needs to join the Julian army if he wants a hope of defeating the Rainbloods.
A: "I suppose that even with the Bishop defeated, the King and Queen are more powerful still...They would be very difficult opponents to defeat alone."

=== ADDENDUM OVER, NOW LET'S ACTUALLY START CHAPTER 5 ===

=== MAYA ===

[1]
R: Extra comma.
A: "The people of Maya are rather extraordinary."

[2]
R: Clunky ending.
A: "We can't communicate with them while they're asleep."

=== BATTLE 18 ===

[3]
R: "What?" is incorrect here. Benetram's just figured out why the houses are flying.
A: "Wait. Couldn't it be because they are safer from enemies up there?"

[4]
R: Generally unnatural wording.
A: "That explains it. The people of Maya are taking to the air to avoid dark forces on the ground."

[5]
R: This is the leadin to the fight, so it needs to be a little clearer what's happening.
A: "We're close to civilisation, but...I can sense evil approaching. A very powerful evil. Be careful!"

[6]
(advice screen)
R: "Disadvantage" and "advantage" right next to each other is a bit repetitive.
A: "Let's engage where we'll have the upper hand."

Chapter 5 is generally a LOT cleaner than chapters 3 and 4 were. Also oh god Gabriel is here IT'S ALL COMING FULL CIRCLE-

[7]
(Cutscene after battle 18)
R: Comma splice.
A: "Primula will explain, but it is not just a hill. It's more like an ancient monument."

[8]
R: 'Yes' is odd.
A: "Goodness, we really are above the clouds. We're up so high!"

[9]
R: Repetitive, and 'old book' feels weak.
A: "Elder, what about that old tome? It should be written in there somewhere."

[10]
R: Same as 9.
A: "Oh yes...That book should have the answer."

[11]
"Master Gabriel. The book, remember?"

[12]
"While that book is being fetched,"

[13]
R: Run-on sentence, comma splice, the works.
A: "Poor young Julian, after what Galm did to his father...But what a strong man you've become since then!"

[14]
R: Strangely worded.
A: "What? Do you think I'll let you down just because I can't match your brawn, Knight?"

[15]
"The tome of the dark temple is nowhere to be found!"

[16]
"We've been protecting that book for 1,000 years in preparation for your visit. I'm deeply sorry we allowed it to be stolen."

After some examination I've decided that there are too many instances of 'old book' to be worth screenshotting every one. I'd honestly suggest a find+replace job on the script segment to switch it up. In a lot of cases I think 'book' flows a lot better than 'old book' does, actually. "Old book" draws too much attention to itself, if that makes any sense.

=== MAYA (but on the ground this time) ===

[17]
R: Ambiguous comma placement. (Could be initially read as him observing the Creator, only for the meaning to change halfway through the sentence. This is known as a 'garden path sentence'.)
A: "Like the Creator, he observes but lends no assistance."

[18]
R: A bit stiff.
A: "This explains why the Bulzome Sect hasn't attacked Maya. They've been taking advantage of us."

[19]
R: Another garden path sentence. (Initially read it as 'the Creator WHO IS FROM Remotest')
A: "For the next 1,000 years, Remotest must not acquire the knowledge the Creator has bestowed upon Maya."

[20]
R: Weirdly ordered.
A: "Elbesem blessed Maya with a mechanical defense in ancient times, and our houses were made to fly."

[21]
R: Unnatural first sentence.
A: "Everyone who lives in the northern region has yearned for a world that isn't snowbound at least once."

[22]
R: "First of all" is used incorrectly here.
A: "The primary cause for most machine failure is the natural deterioration of parts due to age."

[23]
R: This and 23a are awkward. I'm trying to be very careful with these lines because I understand they're explicit references to StHA, but 'fire' can't possibly be the right word here.
A: "Do you remember, Julian? The Vandal that claimed Endrich, and the hero Arthur who saved the kingdom?" "Along with Rodi the ninja, Melody the shaman and many others, he prevented the chaos from spreading to other countries."

[37]
(Apologies for the misordering but I missed this the first time and had to go back for it)
R: This and the following line 37a are stiff.
A: "But if it's the only way to make people see me as a man, then I'll do it!" "Hahaha, I drank it! -Hiccup- But, uh...now my head feels like it's going to crack open..."

=== BATTLE 19 ===

[24]
R: Weirdly worded.
A: "I'll present myself to the sensor so the monument can identify my Spirit."

[25]
R: Passive.
A: "Dark beasts will appear soon. Julian, you must prepare the army."

[26]
(advice screen)
R: Poorly worded.
A: "Julian, the beasts in the sand and on the plains appear in response to our movements! If you sense danger, stand still!"

[27]
(post battle cutscene)
R: Second sentence is a mess.
A: "This is strange. We've defeated the enemies, but there's still nothing happening..."

=== ARK HILL (Battle 20) ===

[28]
R: Second senctence is very stiff.
A: "But from how our voices are echoing, we must be in a large hall of some sort."

[29]
R: Second 'of' is redundant.
A: "This is not only a test of your ability, but also the abilities of those who support you."

[30]
R: Trainwreck.
A: "These clay dolls will begin to move. You must control their movements to ensure they gather around Gracia."

=== POST EVOLUTION CEREMONY ===

[31]
(Say yes when Gracia asks if Julian wants to be blessed first)
R: Weird structure, weirder punctuation usage.
A: "As leader of the Julian army, you more than anyone should be first to receive the blessing."

=== BOWLET CABIN ===

[32]
R: First and last sentences are too similar to each other.
A: "This was my mistake."

[33]
R: Comma splice.
A: "I was born south of Destonia, so I know nothing of snow."

[34]
R: Somewhat mangled.
A: "I've heard rumours from the other people in this cabin. They say that a snow witch is the one causing this storm."

[35]
R: ~KateLine~
A: "It would've been faster to take the regular path back to the Ancient Road."

[36]
R: Oddly ordered and clunky.
A: "We should try to avoid battle in the mountains. The cold will sap our strength, and we don't have any experience fighting in the snow."

[38]
R: Awkward.
A: "I'm the snow witch, Marky. Everything I touch turns to ice."

[39]
R: "Suck out" sounds off. Go for drain or just 'suck'.
A: "I freeze humans and drain their blood."

[40]
R: She's just repeating her previous line here. Punch it up a bit so it's not too obvious.
A: "Now let the cold consume you so I can feast on your life!"

[41]
R: A little stiff.
A: "How strange. You should have frozen to death by now. I'll make my blizzard stronger, then..."

[42]
R: Again, stiff.
A: "Impossible! No human should be able to survive my blizzard! Who are you...?"

[43]
R: ~KateLine~
A: "You're clearly very powerful, but it was reckless of you to come here all by yourself."

[44]
R: There's a joke to be made about how Marky's stiff lines need thawing out but I can't find the words for it.
A: "That's right. And it looks like I've found some new friends to play with."

[45]
R: Slightly awkward.
A: "I do this to survive! And I won't stop until someone frees me from my misery. Maybe you will be the ones..."

[46]
R: So my reading of Marky so far is that she wants to die because she knows what she's doing is awful, but also she wants to live in order to get her revenge on Bulzome. With that in mind, I'd adjust this and 46a to make it more obvious.
A: "Perhaps going without nourishment would be the right thing to do..." "But I refuse to die until I've had my revenge on Bulzome, the bastard who did this to me!"

[47]
R: Stiff. Also it's a direct response to Gracia saying 'we shouldn't fight her outside', so connect the lines. I'd also tweak the next line a little.
A: "But if you stay here, the blizzard will continue. And your stocks of food and firewood will only last so long." "Die slowly in this cabin, or die quickly at my hands. It doesn't matter to me."

[48]
R: Stiff, and oddly it's worded as a question with no question mark.
A: "Creating blizzards by controlling nature itself...she must be immensely powerful."

[49]
(after Marky's appearance)
R: This guy was talking about how the snowstorm was a sign of the end times before Marky showed up, so this statement seems extremely disconnected from that. Make it clearer he was exaggerating before.
A: "I didn't really think the blizzard was that strange. The weather is always unusual around the end of the century. I was just having a bit of fun..."

=== BATTLE 21 ===

[50]
R: Calling her 'Marky the snow witch' here feels a bit awkard.
A: "Where's the snow witch?"

[51]
R: Escape seems odd when she's the one holding them hostage. Applies to Marky's response in 51a as well.
A: "Did she retreat?" "Retreat? Me?"

[52]
R: Clunky.
A: "Ha...if you can't see me, I suppose I'll have to reveal myself. Behold!"

[53]
R: Again, clunky. (I'm really unsure why she's saying 'you are brave, aren't you?' at the end. My best guess is she's commending Julian for picking the fast death over the slow one.)
A: "Here I am! Witness my fortress of ice. You have no hope of defeating me, but clearly you have the courage to die trying."

[54]
R: A bit childish, but it's hard to write an alternative that doesn't copy the following line from Benetram.
A: "Julian, Marky will be much more comfortable fighting in these conditions than we will."

[55]
R: A followup to him saying Marky is favoured in this fight, so needs a connection. The followup line 55a is also rather stiff.
A: "Even so, we cannot afford to lose this fight." "Ice and snow will have little effect. We must find another way to defeat her, Julian."

[56]
(advice screen)
R: First sentence is clunky.
A: "We are fighting a snow witch, so use fire and avoid ice-based attacks."

(Post-battle cutscene; Marky dies)
[57]
R: The comma implies a shift in tense and makes the reading a little weird.
A: "The enchantress of Bowlet Mountain, dying as a snow witch...How pathetic..."

[58]
R: Minor ~KateLine~, major ~KateWasn'tPayingAttentionInThePreviousCutscene~
A: "So you weren't always a snow witch?"

[59]
R: Generally odd.
A: "The Innovator was a child like this...Why couldn't I sense it? But it's too late for me now...I'm dying..."

[60]
R: A bit mechanical.
A: "I may have lived in this body...but I want to die as the person I once was."

[61]
R: I don't think people say this.
A: "Aah...My body feels so light..."

[62]
R: Too much overlap with the previous line from Isabella.
A: "My eyes...are back to how they used to be?"

[63]
R: First sentence is stiff. (Honestly this line breaks Show Don't Tell pretty badly and I'd rewrite it entirely but I don't know if that's too far.)
A: "Anger is rising from the depths of my heart...Anger towards the monster who treats lives like playthings."
MORE AGGRESSIVE REWRITE: "Something's crying out from the depths of my heart...To toy with someone's life so cruelly...I will never forgive Bulzome!"

[64]
R: Awkwardly worded.
A: "Every minute Bulzome stays unsealed is a minute he blights the world with his malice."

(Post-battle cutscene: Marky lives)
[65]
R: This is a response to one of Julian's '. . . . . .' lines, so it should be clarifying what he actually said. In this case it's some variant on 'please stop fighting, this battle is pointless'.
A: "This battle is pointless...? Are you asking me to halt my attack...?"

[66]
R: Why is Kate in pain here??? I'm guessing she's a bit annoyed that Marky didn't figure out they were the Legendary Expedition, but if so 'Oww' is the wrong sound to make.
A: "Oof...You don't believe us? We're the Legendary Expedition."

[67]
R: See 62.
A: "My eyes are back to how they used to be?"

[68]
R: Just weird sounding. "I owe him one" is far too casual.
A: "If you're the Legendary Expedition, that means you're going to challenge Bulzome, right? I...have a score to settle with him."

=== BATTLE 22 ===

[69]
R: Minor tense weirdness.
A: "There's been a lot less snow since we left the mountains..."

[70]
R: Very awkward.
A: "Galm? The Vandal that Julian wants revenge against? Why is he here?!"

[71]
R: Ordering weirdness.
A: "We know about Galm because he is Julian's target."

[72]
R: Needs a comma.
A: "Have you shown yourself to battle Julian, or have you come for another purpose?"

[73]
(Say no when Gracia asks if he should discard the Staff of Besem)
R: First sentence is oddly structured, and 'dominant' is a strange word choice.
A: "Discarding the Staff of Besem before fighting a powerful Vandal risks the annihilation of our force."

[74]
(Advice screen)
R: This paragraph is just...odd.
A: "We're fortunate that Galm is fighting us on even footing. Be wary of his physical strength and wait for an opening to strike."

[75]
R: OK this one is extremely petty but that's how all the best translations go~
There have been numerous references to Greek gods in the equipment/spells throughout the game. There's the Thanatos summon, the Apollo and Artemis Pins, and the Cocytus glove. Notably, the Apollo Pin's original name was the Mars Chain, but it was presumably changed to Apollo in order to stay consistent with the Greek references (as Mars is the Roman equivalent of the Greek god Ares).
With that in mind, Proserpina (the Roman name) is a massive outlier. In order to remain consistent with the rest of the translation I'd rename it as the Greek equivalent, Persephone.

[76]
(go the wrong way when walking back to battle 22)
R: First sentence is completely wrong.
A: "Where are you going? We need to hurry, Julian. Bulzome must be sealed as quickly as possible."

(77)
(post-battle cutscene)
R: Weird wording.
A: "You promised, Galm. Please tell us how to climb the cliff and reach Bulzome Temple."

[78]
R: A lot of unnecessary words.
A: "The shrines on either side of Bulzome Temple...hold the keys..."

[79]
R: Again, overly wordy.
A: "The non-Innovator forces must attack from the sides. Once they capture the shrines, the passage to Bulzome Temple will open."

[80]
R: This and Galm's response (80a) are in desperate need of context.
A: "But only telling us this much...that's..." "-laughing- That's why you're here, Gracia. That moment...will be your time to shine..."