Alright, lets take a look at this!
Quite an odd song name, however I checked around a bit and indeed it seems correct lol.
[General]
General Hitsounding: Good job improvising, it sounds nice, but it still sounds rather bland, for example, you used soft set at the calm parts (which is excellent), but when the epic part of the song kicks in, you still have a soft hitsound set, just with higher volume. I find that quite a turnoff. Consider using normal hitsounds at some points as well, it would add to the dynamics and give off a better feel of the song. Also I think the volume changes are too drastic, they shouldn't be double the value on consecutive timing sections. What I mean by this, is that a change from 40% to 80% is too sudden and sometimes a bit startling. You should make it noticable, yet subtle. I see you used 25%, 40% and 80%, try using 35%, 50% and 70%, the changes would still be there, they just wouldn't be that sudden. (Use lesser values for normal hitsounds though, like 60%).
[Ikaros]
Difficulty Settings: AR -1. AR9 really doesn't fit here, and AR8 is just fast enough so everything is readable (even the overlaps). Also the song is too calm for AR9. I would actually suggest OD7 as well because the song doesn't give off a "hard" feeling to me, but OD8 isn't bad either, your pick.
00:01:657 (3) - Whistle at the start? It seems a bit bland without any hitsounds here, and emphasizing the vocals sounds nice. This also applies to 00:04:714 (3).
00:12:931 (1) - This spinner ending where it does now sounds awfully wrong. You should totally end it at 00:13:695. Additionally, the volume change to make the finish more quiet goes against what that finish should present, and that is a "heavy note" how I like to call it, which is located at 00:13:695 and not where it is now, so you should remove the volume changes as well. If you think the spinner is too short, try mapping the melody/vocals instead, just like you did at the end.
00:22:580 (x) - I expected a note here, since you used it at 00:16:466 (5) to follow the drum. I would suggest adding a note here to make it sound better and more consistent.
00:23:822 (1,2,3,4) - Just gonna leave a comment on these. I don't like them, because they go against a more interesting rhythm to me(the melody of the guitar). Also they are stacked at the slider end, and that stacking seems a bit random to me. If you really want to keep your notes, I highly suggest to remove the new combo on that 1, use lesser spacing on 00:23:058 (1,2) and keep the spacing consistent throughout the combo, without stacking anything. Feels much better if you ask me.
00:27:453 (4,5,6,7) - This spacing is super awkward. Antijumps like this are bad if you ask me. They break the flow and seem rather dull, I would be much happier if you made jumps out of these notes. This goes for all notes made in this way.
00:29:555 (1,2,3,4,5,6,7,8) - Just a suggestion regarding this whole combo, to make it more interesting, you should decrease the spacing a bit throughout the whole combo, because that would give off a feeling of an echo of the first vocal (the 2nd vocal). That is, after removing those really awkward antijumps. Especially since you used lower volume here.
00:36:625 (1) - This new combo is bad because it breaks consistency for no reason (take a look at 00:33:568 (4) for example, you didn't use it there). The next problem is, while 00:37:007 (2,3) follow the vocals, they miss out on a really good part of the music, which you only mapped half of (I am talking about 00:37:771 (1,2,3,4) here). What you should do here is put a new combo on 00:37:007 (2) instead, and map the synth instead. This also means a removal of the new combo at 00:37:771 (1).
^ Just an example of the timeline how I think it would sound much better. Also consider using a normal hitsound set for those, makes it much more dynamic. (actually you did this at 00:49:045 (1,2), and that's so much better in comparison)
00:51:147 (1) - You really don't need this new combo. You should move it to 00:51:912 (5) to follow the music better, and also remove it from the next note. Same applies to 00:54:205 (1) for the same reason.
00:53:440 (6) - This should be a new combo, not 00:53:631 (1).
01:01:848 (1) - While this spinner is okay, I don't like it. There are a few distinct notes in the music(the vocals) which, if mapped, would be a far better solution if you ask me. You could, for example, make that each note has higher volume than the previous one for an even more dramatic feel.
01:13:313 (11,1,2,3) - I think these 4 notes would belong in the same combo. So use a new combo on 11 and remove it from 1. Also put a new combo at 01:14:268 (4) in that case, cause it starts a new vocal section. The spacing and patterns might have to change a little to accustom this, but I believe that follows the music much better and is a good change.
01:18:281 (6) - I think you should remove this note and reposition the combo a little to fix any possible spacing errors. It doesn't follow the music nicely and makes the rhythm here pretty boring, cause it doesn't exist where you used sliders at 01:15:033 (1).
01:24:969 (1,2,3,4,5,6) - An overmapped stream.

Only the notes 5 and 6 follow the music. Consider changing this to follow the music better, i.e. remove notes 2 and 4.
01:25:542 (7,8,1,2,3,4) - I strongly disagree with this comboing. You should totally put a new combo on 7, remove it from 1 and put it on 2 instead. Like that it follows the music so much better.
[Astraea]
Just wondering, but, why use Ikaros picture here? Maybe try finding a good Astraea picture? If you need help with it, let me know and I can help you find one I guess.
00:01:657 (3) - Same suggestion like in the Ikaros diff, try using a soft whistle at the start here for same reasons. Same applies to other spots mentioned there as well.
00:12:931 (1) - Yeah this spinner as well. Should totally end it sooner. However, it could be a bit hard to complete nicely and would seem a bit sudden, so I would prefer if you change it to the thing I suggested in Ikaros diff for the same spinner.
00:15:415 (1) - This new combo is totally unnecessary. Remove it.
00:16:943 (1,2,1,2,1,2,1,2,3) - This whole section is rather boring. No offense, but this is a hard diff, you shouldn't spam 1/1 rhythm here. Try following the melody, it would work much better. Also avoid stuff like 00:20:001 (1,2), while they are readable, they aren't really expected because the music doesn't exactly call for things like that, making them quite unintuitive.
00:26:498 (1, etc) - A continuation of 1/1 spam, please no.

00:37:007 - Among all those 1/1 spam, you should definitely map the synth here, it's too good to miss.
00:50:574 - Finally, the 1/1 spam ends. you spammed 1/1 for 34 seconds almost, man you should definitely change this. :S
Also long sliders like this, well I suppose they are okay, especially if you decide to follow the melody until this point, but I think it's a bit easy for a hard diff. So far, this diff looks like a normal diff with awfully wrong difficulty settings and a fast SV.
00:56:689 (1,1,1,1) - Yeah, well I don't like this at all. You ignored pretty much anything interesting in the song.
Try something like
this.
00:59:746 (1,2,3,4,5,6,7) - This sounds awfully wrong to me. You follow the vocal, then you stop for whatever reason, then you continue, however the way you mapped it is a complete mess. Try
this. This follows the music quite well and sounds rather nice.
01:05:096 (1,2,3) - More 1/1 :/, map the vocals please (add notes 01:05:287, 01:05:670, etc).
01:07:198 (1,2) - This new combo should be on the note 2, not 1. In addition, you should map the vocals like I suggested above. I will stop suggesting this for now, it should be obvious by now.

01:14:268 (5,1) - 5 should have a new combo for consistency reasons, not 1.
01:23:440 - Just pointing out this section that this is how this whole section should look like (not exactly like this, cause if you only use this, it would be boring, but I mean the density of notes used on the timeline).
[Nymph]
That doesn't look like Nymph to me, on the background pic. Same thing as the above diff.

00:00:892 (1) - You don't have this clap in other diffs, probably best to remove it.
00:13:886 (1) - This spinner should start at 00:13:695 cause of the music. The end seems ok. However, after the spinner, that big unmapped space is too big if you ask me, try adding notes at 00:17:708, 00:18:472, and 00:19:236. It would preserve the rhythm for a normal-like diff and it would make it less boring too.
00:24:587 (1,2,3,4,5) - Noone says that normal diffs have to be 1/1 spam. Feel free to follow the music. Look
here.
00:32:230 (5) - Stacking like this is unfitting for a diff like this. While you did spam 1/1 everywhere, the problem is, it's not really intuitive and new players could click it too early. Should definitely unstack this. This applies too all stacks like this.
00:36:052 (1) - Hm, well, keep it if you wish, but I would prefer if you split the vocal from the melody/rhythm instead of putting all those in one object which ignores most of the music and doesn't exactly map it that well either. The arrow of the slider is quite okay and it has impact (which is good), but the starting point bugged me a bit. Ending point bugs me a bit too, since I find the note at 00:37:771 far more important than where the slider currently ends. Doing something like
this would make it sound much better. Feel free to adjust the usage of hitobjects here, it's just an example of the timeline.
00:58:217 (1) - This new combo is totally unnecessary, best would be to remove it.
01:01:275 (5) - This note is really bad! Goes against the music in every way. Try using a slider like
this. Sounds so much better.
01:02:039 (1,2) - How about removing these? Removing them would make the player focus to the music, also I think it would bring some sort of an impact to the map as well.
01:13:504 (2) - This note should be located on 01:13:313 to follow the music. Sounds so much better.
01:25:733 (5) - Similarly to the above case at 01:01:275 (5), try the same thing here.
01:26:498 (1,2,3) - These go against the music as well, the vocal is located on red ticks. Try
this. Nothing too hard for a normal, follows the music nicely and sounds really good.
01:27:644 (1) - Start it at 01:27:262 instead.
[Taiko Oni]
Overall this looks like a buffed up muzukashii to me. Very simple rhythms and pretty short streams, getting progressively harder near the end.
Use tickrate 1.
00:06:243 (1) - I don't like this spinner, looks off to me for some reason. I suggest to map some notes here instead. If you really want to keep it, make it end at 00:07:580 instead.
00:55:733 - Add a d?
00:56:020 - Add a k?
01:01:848 (1) - End it at 01:02:612.
01:10:256 (44) - Change to D? Seeing as you love finishes.
01:28:026 - Why not have a spinner end? Just wondering.
All in all a pretty solid mapset, you're on the right track. We should talk in game once you see me, cause I think I can give you some nice suggestions overall, it's a bit hard to explain on "paper" like this. I'm not gonna lie that the map could use some little improvements, but don't worry I won't abandon you haha.

Oh you should totally try to squeeze in another taiko mod or two, maybe someone suggests you some rhythms which are more fitting for an Oni diff. I am not a good taiko player so Oni diffs are slightly out of my reach so I can't do it myself, but I think that such thing is possible for your mapset (making it a bit harder yet not destroying your concept of the map).
Quite a long post and I don't like this new format, so pardon the slightly inconvenient to read format, I will have to think of something for future mods. ><