Lone Wolf: Daisy Walker, the Librarian
Present since the release of the Core Set, Daisy Walker comes with a 3W 5I 2F 2A statline and a 5/9 health/sanity split.
Elder sign: +0. If you succeed, draw 1 card of each Tome you control.
Daisy’s elder sign is nuts. On pro-active tests, the +0 is a pass and she will very often draw two cards as a consequence. It is one of the strongest elder signs effect in the game.
Ability: One additional action that can only by used to activate Tome abilities.
This ability is the identity of Daisy. One extra action per turn is one of the best ability you could hope for. How to consistently make use of this action to advance the game is the puzzle that Daisy has to solve.
Deckbuilding: Seeker 0-5 / Mystic 0-2
Truth be told, Seeker 0-5 is a bit of an overkill for Daisy, which has no trouble gathering clue and does not find much support in the other tasks in high XP seeker cards (Maybe with the exception of Occult Lexicon (3), or a couple permanents).
The Mystic splash is however quite helpful in True Solo. While I do believe that the spells using willpower are a bit of a trap for her, having mystics access brings a lot to Daisy for encounter card mitigation, as well as access to great skill cards such as Promise of Power. The class also enables a handful of usable Tome to support her ability. It also means that Daisy can play Down the Rabbit Hole. XP acceleration is a big deal in True Solo, and Down the Rabbit Hole is probably the best XP acceleration card in the game.
Signature Kit
Daisy’s signature is a slotless asset that giver her two additional hand slots to hold tomes.
While the idea of having a flexible Daisy that has a book for every situation is nice, this card has two things going against it.
The first is common to all assets that add player slots: you need to draw them before completing your set up.
The second is that to make a full use of the Bag, Daisy has to play at least 4 tomes. This, even if you are using the cheapest tomes available, is likely to cost at least 5 actions, 5 card and 8 resources to achieve. I hardly see how you can get more tempo back just from being able to use a couple other tomes.
At least, it is a good commit with two willpower or intellect.
The Necronomicon is a solid weakness for Daisy.
The first bite is the enter play effect, that in Daisy will often results in discarding a valuable tome (hey, that’s a positive for Tote Bag, it at least makes room for you weakness).
The second kick is that it presents a cruel Dilemma: either spend 3 actions and take three horrors to discard it, or double your chance of autofails for the rest of the game. You also give-up any chance to trigger the effect of Daisy’s elder sign.
Overall, I tend to ignore this weakness more than to pay for it. The only exception might be if a big fight is coming and my only solution are big events such as I’ve got a plan, or my build critically needs two hand slots.
Preformance review for True Solo tasks
Clue Gathering
With 5 in Intellect and a full Seeker access, it is hard to give any note but the best to Daisy.
On top of that, in the Scarlet Key’s, Daisy finally received a tome that allowed her to investigate on her bonus action: Grim Memoir.
This makes getting clues with Daisy an easy task that speed up scenarios, which reduces the burden of the encounter deck.
She is a top tier clue gatherer, no doubt about it.
Enemy Management
With a 2 in Fight and Agility, Daisy needs to find other tools to manage enemies.
Using her Mystic splash does enable a strategy that use spells to fight / evade enemies, but this strategy has a heavy set-up cost, as Daisy needs not only to play her books, the spells, and boost her Willpower to a usable value.
The other option is to use the Occult Lexicon, backed up by events such as Occult Invocation and I’ve Got a Plan.
However, these options are still expensive and an early stream of enemies can easily overwhelm Daisy.
Mythos Defense - Survivability
3 in Willpower and 2 in Agility is slightly bellow par, but still manageable. The 2 in Agility hurts the most, as treacheries that test it often deal damage, and Daisy has only 5 health.
Still, her access to the mystic class allows her to play with a safety net, using cards such as Deny Existence and Ward of Protection.
On the most aggressive campaigns damage wise (looking at you Forgotten Age), Daisy will require a bit of deck adaptation. Otherwise, she will be fine.
Action efficiency - Economy
An extra action every turn is about as good as you can get as an ability, and at this point, Daisy is quite close to it.
In the early days, her ability was balanced by the lack of Tome to use her action on to progress the game. These days are gone now.
On top of the ability, Daisy enjoy the benefits of being a Seeker, and having therefore access to their powerful mobility and economy cards.
As early as scenario 1, Daisy can routinely get 5 action worth in a turn, by combining her ability with the likes of Shortcut / Eon’s Chart, etc.
Deckbuilding ideas
Daisy is a compulsive researcher

In this deck, Daisy impersonate Mandy, as she is built to draw/search into her deck every round. The idea of the deck is to rush the assembly of the Pendant of the Queen, then use Enraptured to keep adding charges to it.
The intended game loop of this deck is to play either Grim Memoir, Old Book of Lore or Whitton Green as a starter (or Backpack, should neither of the two be in your opening hand).
The deck is built around the following synergies:
Grim Memoir allows to both use Daisy‘s free action to progress the game, and generate in turn draw (which triggers Cryptic Writing).
Old Book of Lore / Backpacks / Whitton Green all have strong search effect that will enable assembling the Pendant of the Queen in no time, while triggering Astounding Revelation for resources / secrets on Grim Memoir.
Occult Lexicon / “I’ve got a plan” / Mind over Matter are tools to keep her safe from enemies before she gets the Pendant, and for boss fights.
Practice Makes Perfect is another search, with 3 powerful targets: Perception to accelerate card draw, Promise of Power for emergencies/mythos protection, and Enraptured, that can reload both Grim Memoir and the Pendant of the Queen.
The deck is completed by 1X Pathfinder for extra mobility, but this can be swapped for another two XP value card, such as Knowledge is Power.
This deck is perfect for use with Down the Rabbit Hole, as almost all of the cards have upgrades.

Thanks to Down the Rabbit Hole, this deck is easy to reach even in the campaigns that grant low XP (though I would adapt it in Dunwitch to include 2X Deny Existence for protection against Beyond the Veil).
Daisy swings the doomed book

At level 0, this deck is easy to pilot. It sacrifices some of the searches and late game combo of the previous deck for more Mythos protection, in the form of Deny Existence and Ward of Protection
The game plan is quite simple: use Grim Memoir to investigate with bonus actions, find your tomes with Laboratory Assistant and Research Librarian, and have enough cards to deal with enemies with the likes of Occult Lexicon, “I’ve got a plan” and Occult Invocation.
Resources for this deck are generated with Crack the Case and Cryptic Writing. The deck has enough search potential for Astounding Revelations to be good, but the seeker pool is wide enough to have some variety.
Calling in Favor, while it can help re-trigger Lab-Assistant, is mostly there to support the upgraded deck.

My evaluation of Daisy True Solo power level
Daisy Walker is a clue getting beast. In multiplayer, her versatility in playing cluever / support with very high efficiency makes her S tier for me.
In True Solo, she is reeled in a bit as she does not have the best statline to manage enemies on her own. And while in the modern card pool, Seekers have decent options to deal damage / evade, most of them are not the most efficient, especially early in a scenario. Having to play an Occult Lexicon and a Blood-Rite is expensive resource wise. Occult Invocation is great but depleting your hand before the set-up is complete is annoying. You need to get clues before using “I’ve got a plan” effectively, etc.
For this reason, a couple early enemies can throw a wrench in Daisy’s plans. Otherwise, Daisy is geared to breeze through the location vacuuming clues at a record pace. Thanks to Down the Rabbit Hole, Daisy’s decks also upgrade faster, which helps to achieve long term success in a campaign.
Given these observations, my rating for Daisy in True Solo is: