DARK SOULS II: Scholar of the First Sin

This is as simple as getting all of the other achievements in the game. Once your penultimate achievement pops this one will unlock.

Here is a basic overview of the achievements so that you know which ones to look out for and which ones to not worry about. They are also generally ordered chronologically (although that is based on the order in which I think you may play) within their given title:

Story-related:

These achievements are not missable and you will get by playing through the game normally. Only titles are used to avoid spoilers (except for Curious Map).

- Self Recollection
- Last Giant
- Sinner's Bonfire
- Iron Keep Bonfire
- Gulch Bonfire
- Brightstone Bonfire
- Looking Glass Knight
- King's Ring
- Ancient Dragon
- The Heir

- Curious Map: this will unlock if you get all of the above, and light the bonfires.

Covenants:

These achievements are gained by discovering the covenants, keep the locations (after comma in brackets) in mind so you don't miss them. These are easy and not missable.

- Covenant of the Meek (Way of Blue, Majula)
- Covenant of the Fittest (Company of Champions, Majula)
- Protector Covenant (Blue Sentinels, Cathedral of Blue)
- Clangorous Covenant (Bell Keepers, Belfry Sol/Belfry Luna)
- Sanguinary Covenant (Brotherhood of Blood, Undead Purgatory)
- Brilliant Covenant (Heirs of the Sun, Harvest Valley)
- Gnawing Covenant (Rat King, Grave of Saints/Doors of Pharros)
- Abysmal Covenant (Pilgrims of Dark, Black Gulch/Shaded Forest/Drangleic Castle)
- Covenant of Ancients (Dragon Remnants, Iron Keep via Dragon Shrine)

- Selfless Giver: max-out devotion to covenant, I suggest you do this with the Pilgrims of Dark, it is the easiest and will come if you want PvE completion anyway.

NPCs:

Some of these achievements are missable!

- Change of Clothes: give Rosabeth some clothes after you unpetrify her before the shaded forest. (Missable if she dies, see detailed guide).

- Gathering of Exiles: this is missable if any of the NPCs die.
Get the following NPCs to go to Majula:
- Merchant Hag Melentia (Forest of Fallen Giants)
- Cale the Cartographer (Forest of Fallen Giants)
- Licia of Lindeldt (Heide's Tower of Flame)
- Carhillion of the Fold (No Man's Wharf)
- Stone Trader Chloanne (Harvest valley)
- Laddersmith Gilligan (Earthen Peak)
- Rosabeth of Melfia (Majula; path to Shaded Forest)

The following are achievements based off getting special equipment from certain characters, you will have to perform certain tasks before doing parts of the game (Recommend seeing their detailed guides). These are not missable as you can get them with bonfire ascetics to redo areas if you need to:

- Smith for Life: Inherit equipment from Steady Hand McDuff.
- Garrulous Miser: Inherit equipment from Laddersmith Gilligan.
- Reflections of Disembodiment: Inherit equipment from the head of Vengarl.
- Lucatiel: Inherit equipment from Lucatiel of Mirrah. * Missable.
- Moonlight Greatsword: Inherit equipment from Benhart of Jugo.
- Hold the Fort: Inherit equipment from Captain Drummond.

Collected Items:

These are not missable (try not to kill NPCs, but if you do then use their gravestone), but getting all of the spells will either mean a lot of PvP to max certain covenants, or going to NG++ and buying them from Chancellor Wellager in Drangleic Castle. They can all be gained across multiple play throughs (e.g. if you miss a gesture, then get it in NG+).

- Gesture Maestro: Find all of the gestures, all but one are learned from talking to NPCs, the other is from the Sunlight Alter (statue in Harvest Valley).
- Master of Sorcery: Find all of the sorceries in the game.
- Master of Miracles: Find all of the miracles in the game.
- Master of Pyromancy: Find all of the pyromancies in the game.
- Master of Hexes: Find all of the hexes in the game.

Miscellaneous:

- Supreme Weapon: Upgrade a weapon to +10, unmissable.
- Vendrick: kill Vendrick.
- This is Dark Souls: Die. If you haven't died after a small amount of time playing then you are amazing and I suggest you continue to go deathless if possible to get the special ring. Otherwise, jump off a cliff.

There are plenty of other guides out there, so this is more a guide for efficiency. Many thanks to WallRunnrNinja for getting me started on the roadmap.

First Playthrough
For my first playthrough, I did absolutely everything. Found every spell I could, beat every boss, gained every missable, gestured every gesture... did everything. This included using a single Bonfire Ascetic on the Primal Bonfire guardians in order to take their NG+ soul to Straid for the exclusive spell.

With everything I could possibly do, already done, I wanted to speed through the subsequent playthrus as quickly as possible.

First, make sure you have a bunch of Bonfire Ascetics available. There are plenty to find and a number of merchants have them for sale. Make sure you buy a bunch before you start the next play.

Second is "nice to have", but certainly helps with the soul gain. Have a full set of gear that boosts your souls earned when you kill enemies. I used:

Head - Warlocks Mask (Fragrant Branch in Shaded Ruins) - 2.5% Soul Bonus, also boosts Intelligence slightly. Can also use Nahr Alma Hood if you don't have a spare Fragrant Branch (see "Chest")
Chest - Nahr Alma Robes - 10% Soul Bonus (Kill Titchy Gren behind the Executioner's Chariot then buy from Merchant Hag).
Gloves - Jester's Gloves - 10% Soul Bonus (Buy from Magerold in Iron Keep). Can also use Tseldora's Manchettes (see" Legs") but Jester's offers much better protection.
Legs - Tseldora's Trousers - 5% Soul Bonus (Kill Maughlin in Majula).
Ring - Covetous Silver Serpent Ring +1 - 20% Soul Bonus (Spend 10,000 at Merchant Hag then Talk to her). The +2 ring is better (30%), but would need to Ascetic the Mytha boss fight. I chose to save it for next playthrough.


Second Playthrough
The first objective is to reach a 2 Million Soul Memory to open the door at the Shrine of Winter instead of lighting the 4 Primal bonfires. The second objective is to have enough Hard souls in your inventory to reach 3 Million Soul Memory in the Third Playthrough.

Before you go too far, check your Soul Memory. Its the number in top-right corner of your Stats screen. You want to have 2 Million more than this number.

My roadmap was as follows:

Things Betwixt (Just run straight through)
Majula
Forest of Fallen Giants, Last Giant Boss (Soldier Key, need it later)

From here I wanted to pick up the Covetous Silver Serpent Ring +2 and fight Old Iron King, but repeatedly fighting Rotten works just fine too.

Heide’s Tower of Flame, Dragonrider Boss
Exhaust dialogue with Licia of Lindeldt
Majula, pay Licia to move path
Huntsman’s Copse, Skeleton Lords Boss
Harvest Valley, Covetous Demon Boss
Earthen Peak, Mytha Boss (Equip Covetous Silver +2 Ring)
Iron Keep, Old Iron King (You can skip Smelter Demon)

From here I used those Bonfire Ascetics to repeatedly fight the Old Iron King. With all the Soul Bonus gear equipped, I would gain around 250,000 souls per kill, as well as two Hard souls - Old Iron King Soul (25,000) and Old King Soul (75,000). The Old King Soul is one of the most valuable of the Hard souls in the game. The Old Dead One's Soul dropped by Rotten gives 60,000, so the difference is negligible if you prefer this fight, but as a Sorcerer, Old Iron King was easier for me.

After roughly 5-6 fights, I had the 2 Million Soul Memory needed to open the door at the Shrine of Winter.

Majula, use Fragrant Branch of Yore on Rosabeth
Shaded Woods
Shrine of Winter
Drangelic Castle, Dragonrider Bosses and Looking Glass Boss
Shrine of Amana, Demon of Song Boss
Undead Crypt, Velstadt Boss
Obtain the King’s Ring
Drangelic Castle (King's Gate)
Throne of Want, Defender and Watcher Boss (to avoid fighting them just before Nashandra)
Shaded Woods
Aldia’s Keep (ignore torches, run past the dragon skeleton and down the hallway), Guardian Dragon Boss
Dragon Aerie (ignore everything, go across the zipline and run across the bridge)
Dragon Shrine (ignore most the enemies)
Speak with the Ancient Dragon to obtain the Ashen Mist Heart
Forest of Fallen Giants (Use Soldier Key)
Memory of Jeigh (Below Cardinal Bonfire), Giant Lord Boss (Giant's Kinship)
Throne of Want, Nashandra Boss, NG++ Unlocked

BEFORE you transition to your third playthrough, you want to collect as many Hard souls as possible so you can reach the 3 Million Soul Memory marker unlocking the Shrine of Winter. To do this, you can gain a Soul of a Great Hero (20,000) every 60 seconds.

Travel to Dragon Aerie bonfire
Run straight ahead and over the bridge (use Fragrant Branch)
Collect the Bonfire Ascetic, return to bonfire (Aged Feather)
Climb the ladder, use the Zipline and drop off after the bridge onto the island with the Soul of a Great Hero.
Return to bonfire (Aged Feather), use the Bonfire Ascetic

Once you run that a few times it will only take 1 minute to gain a new Soul of a Great Hero, for as many times as you need it. Only one Fragrant Branch is needed, this persists through the Ascetic. The amount of times you need to do this run depends on how many other souls you have. For me, with all the other souls I had, I only needed 50 Soul of a Great Hero, which took just under an hour. To give you an idea:

99x Soul of a Great Hero = 1,980,000 Souls
6x Old Iron King Soul + Old King Soul = 600,000 Souls

Once you have 3 Million worth of Hard souls, you're ready to speed through your final playthrough, which should take around 30 minutes. Check your Soul Memory before you do, just to be sure.

Final Playthrough
Things Betwixt (Just run straight through)
Majula
Forest of Fallen Giants, buy Fragrant Branch from Merchant Hag (12,000). Use Hard Souls if needs be.
Majula, use ALL your Hard Souls. Check your Soul Memory to make sure it exceeds the required 3 Million.
If for any reason you have come up short, don't fret. Pick the boss of your choosing and don your Soul Bonus gear and get to fighting. Rotten is nice and quick to get to.
Use Fragrant Branch of Yore on Rosabeth
Shaded Woods
Shrine of Winter
Drangleic Castle, talk to Chancellor Wellager to buy the remaining 2 Miracles and Pyromancy.

Achievement(s) unlocked!

I made a spreadsheet which combines a lot of information from a lot of TA achievement guides, some Wiki information, and my own simplification/amendments, into one place for easy viewing so that you don't need 50+ browser tabs open and keeping a constant mental note of what to do and where. You can download it and mark things off yourself.

https://1drv.ms/x/s!Asr4z0Bu0rVYoaEjUipO37zn2ESYIQ?e=te7Z6n

The only Excel tab you need to really keep an eye on is the Equipment tab, since it involves talking to and summoning people at certain points through your progress, which if you're not careful will lock you out of Benheart/Lucatiels achievements.

The Equipment Achievement tab also includes a map with a visual representation on what areas you need to watch out for/what order to do things in, including where you'll find Fragrant Branches of Yore amongst other useful things. I find that it's best to tackle Lucatiel's route first and follow Benheart's route after.

Unlike Dark Souls 1, you don't immediately process to NG+ or NG++ after defeating the final boss - you have to trigger the new run from Majula's bonfire. This means that nothing else (except maybe the NPCs for the Majula Population achievement) is missable SO LONG AS YOU DON'T USE ANY BOSS SOULS OUTSIDE OF SPELLS/PYROMANCIES/HEXES/MIRACLES.

I didn't write out 95% of the information on that spreadsheet, and I made it for myself years ago because I was sick of constantly flicking between websites and guides. But after quitting the game for years and coming back very recently to finish it, this spreadsheet really helped me get back on track quickly and continue through into NG+ and NG++ with ease.

I hope this helps you as it helps me, and thank you to everyone for the information provided in the first place.