【FGO】"Skill Reload" Append 5 Guide & Personal Priority/Recommendation

FGO Anniversary 2024 was another meta-defining anniversary update, and this time it didn't come from a Servant, but a gameplay update instead.
"Skill Reload" was introduced in the 9th Anniversary as the 5th Append Skill for all Servants, costing 120 Servant Coins to unlock.
Its effect is simple, yet very effective: Reduce a Servant's skill cooldown by 1 the first time it's used in each battle. At Lv1, it can be used one time; at Lv6~9, it can be used twice; and at LV10, it can be used 3 times.
This has an immediate impact on a lot of Servants, as well as having the potential to cascade out of control when combined with Servants that can also reduce cooldown, similar to how Koyanskaya gave birth to the Buster Looping Meta.
This power, however, does not come cheap. It has a steep cost of 120 Servant coins, which does not come easy unless you can afford to roll multiple copies of that Servant or have them at high Bond, and sometimes conflict with Mana Loading, another useful Append skill that many people (inlcuding me) already spent their coins on.
This guide is an attempt to showcase which Servant you should prioritize Append 5 on, as it can massively improve their performance.
As this game now has over 400 Servants, I simply cannot cover everything, and this list below is just my personal recommendation. There might be cases where I'm wrong, so try to critically think before you follow my advice and unlock this new append.
Thankfully, Lasengle already confirmed that we can switch Append skill around in a future update, so you don't have to be afraid to experiment.

Arcueid:
Arguably the biggest winner from Append 5. Just one less cooldown on her battery pretty much fixed all the problems she previously had. She can now run WKoyan with any MC and CE, she can plug in Oberon if she needs more damage, she can run Single Koyan + Atlas + any 50% charge Support, etc.

Aesc/Summer Morgan:
Same as Arcueid, one less cooldown on her S1 battery was all she needed to fix her awkwardness with WKoyanskaya. Combined with the recent Merlin upgrade, she can now even run BG + WKoyanskaya + Merlin and give Oberon a rest. Swap Oberon back in if you need more damage for W3, but the Merlin setup will give her much better damage for W1 and W2.

Summer/Space Ereshkigal:
Pretty much a Servant designed for Append 5. Her performance with and without it is night and day. You always want her Append 5 over Append 2, and you always want to use her with either Atlas MC or Koyanskaya to guarantee that she can reuse all her skills on W3. My preferred team to use for Daily now is Lady Avalon + Castoria, but you can also do WCastoria or Castoria + Koyanskaya.

Summer BB:
The setup I used here applies for all Servants with a 50% NP charge on 7 turns cooldown when they unlock their Append 5. However, for Summer BB, she has a unique advantage over others: her ability to lock her cards and her insane crit damage potential. This allows her to overperform in W3 by guaranteeing that she can follow up her NP with a Buster crit, buffed by 2 stacks of Self-Mod and 2 Koyanskaya.

Altria:
A 4T cooldown pseudo-50% charge is pretty good, who could've thought. A few other Servants can also use this setup, such as Mordred and Lancer Ereshkigal.

Nitocris / Nitocris Alter
They're in a similar situation to Arcueid, but since they're Art instead of Buster, they're less compatible with Koyanskaya than Arc.
For OG Nitocris, since she also has an Instant Death farming niche, I use her to farm the Ordeal Call Las Vegas Free Quest. Aoko is used here as a "Koyanskaya at home" and to Overcharge Nitocris for W1, guarantee that she will Insta-Kill all the Coins. For W2 and W3, Nitocris can reload her S1 to guarantee the Insta-kill instead.
For Nitocris Alter, I use a Castoria + Koyanskaya setup. This does less damage than WCastoria, but in return, she doesn't have to worry about refund at all.

Summer Ibuki
Oh boy. I don't even know where to start with this one.
The sheer amount of things you can do with Summer Ibuki and Append 5 can pretty much make a meta of her own. While the ability to reduce cooldown on a targeted Servant is not unique to her, when you combine it with her status as the best omni Art looper in the game, things escalate out of control very quickly.
I picked 4 setups that I think have the most usability to showcase here.
Some notable things:
- The 2nd setup with Tamamo can outdamage Oberon setup unless Summer Ibuki is running Black Grail
- The 3rd setup with Aoko can farm 1/1/x

There are also many more Servants that I haven't covered yet, either due to me lacking the Coins/Skill level neccessary, or overlapping setup.

Timestamps:
0:00 Arcueid/Archetype: Earth
2:16 Aesc/Summer Morgan
5:02 Summer/Space Ereskigal
8:03 Summer BB
10:50 Altria
13:04 Nitocris
15:21 Nitocris Alter
17:44 Summer Ibuki / Double Castoria
20:23 Summer Ibuki / Tamamo / Double Castoria
23:04 Summer Ibuki / Aoko / Double Castoria
26:09 Summer Ibuki / Yui Shousetsu / Castoria

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