Tomes present themselves as a menu. Pick the interesting one, get some spells, repeat. Played that way they produce a perfectly pleasant empire that never reaches tier V in anything.
Two rules are doing the real work, and neither is stated where you make the decision.
The gates. Tier I is always open. Tier II wants two tomes. Tier III wants four tomes and 3 points in that affinity. Tier IV wants six tomes and 6 points. Tier V wants eight tomes and 8 points — and you may only ever unlock one tier V tome in a game.
The cost curve. Researching a tome is instant; its spells are not. What a spell costs is fixed by how many tomes you held when that tome was selected. The first tome's spells cost 250 Knowledge each. The eighth's cost 2,400.
The two tables worth memorising
| Tier | Tomes needed | Affinity points needed | What it means |
|---|---|---|---|
| I | 0 | 0 | Your opening two picks. Free to take purely for the spell you want |
| II | 2 | 0 | Arrives on its own. Still no affinity requirement, so this is the safe place to take a tome outside your affinity |
| III | 4 | **3** | The first real gate. Culture 1 plus one society trait 2 clears it; culture alone does not |
| IV | 6 | **6** | Culture 2 plus both society traits at 2 each is exactly 6 at turn one. A split culture is one tome short |
| V | 8 | **8**, one per game | You are choosing a single tier V for the whole game. Everything before it should be pointed at this |
| Tomes held when selected | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Spell cost (Knowledge) | 250 | 400 | 600 | 800 | 1,100 | 1,500 | 1,900 | 2,400 | 3,000 | 3,600 | 4,300 | 5,000 |
Past the twelfth tome, each additional tome adds another 1,000 to the cost of its spells. Adept skills are 20 percent cheaper, Expert skills 20 percent more expensive, the Bind Gold Ancient Wonder spell is always 4,000 and Age of [affinity] is always 12,000.
The consequence people miss: spells you buy late are four to ten times the price of spells you buy early. So an early tome's Expert spell is often cheaper than a late tome's Adept one. When you are deciding whether to take a tome now or later, you are also deciding what its spells will cost you forever.
The six affinities
| Affinity | Opposes | Damage channel | What its tomes are about |
|---|---|---|---|
| Order | Chaos | Spirit | Light, faith, justice, government. Buffs, stability and disciplined units |
| Chaos | Order | Fire | Conquest, strife, demons. Direct damage, hordes and destruction |
| Nature | Shadow | Blight | Growth and revitalisation. Farming, druidism, control over the living world |
| Materium | Astral | Physical | Resource extraction, transmutation, golems and siege |
| Astral | Materium | Lightning | Scrying, illusions, enchantment, summoning and meta-magic |
| Shadow | Nature | Frost | Death, decay, ice, deception, exploiting weakness |
Single-affinity tomes grant +2 to their affinity. Dual-affinity tomes grant +1 to each of two.
Planning a line that reaches tier V
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1
Pick the tier V first, then work backwards
You get exactly one, so it is the only genuinely irreversible research decision in the game. The Arch Mage, The Creator, The Chaos Lord and their equivalents are the actual destination — everything earlier is either progress toward the gate or a spell you needed on the way.
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2
Spend your first two tomes freely
Tier I and II have no affinity requirement, and their spells are the cheapest you will ever buy at 250 and 400 Knowledge. This is the right place to take something outside your affinity if you want it at all.
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3
From the third tome, take singles in your affinity
Two points per tome. Culture and society traits give you 6 at turn one if they are aligned, so two single tomes put you at 10 — comfortably past the tier V gate of 8 with room for a dual tome you actually wanted.
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4
Check the count as well as the points
Tier V needs 8 tomes as well as 8 points. If you have been taking only your own affinity you will usually hit the points first and then be waiting on the count, which is a good problem — take cheap tier I tomes in your affinity to close it.
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5
Buy scaling spells early, situational spells never
A unit enchantment bought at tome three for 600 applies to every unit you build for the rest of the game. The same enchantment at tome nine costs 3,000. Situational combat spells rarely justify late prices at all.
The one build where spreading is correct
The Empire of the Cosmos society trait inverts the whole plan. Holding 1 point of every affinity removes the affinity requirement on tier III tomes and pays +20 Mana; 2 of each removes it on tier IV and pays +20 Knowledge; 3 of each removes it on tier V and pays +20 Imperium.
That is the only configuration where dual-affinity tomes are straightforwardly good, because you are trying to be wide rather than deep. It is also slow — you are paying the escalating spell cost while collecting breadth rather than power — so it rewards long games and punishes short aggressive ones.
Two other realm-level exceptions exist. The Unbound Tomes realm trait removes affinity requirements outright, which turns tome selection into a pure cost-curve problem. And in realms with magic victory enabled, researching any tier III tome permanently unlocks Bind Gold Ancient Wonder as an option, while a tier V unlocks Age of [affinity] — so the victory condition can change which tier you are actually racing to.
Mistakes that cost the most
- Taking dual-affinity tomes on the way to a tier V. Half the progress per tome, and you usually cannot tell until you are two tomes short at turn sixty.
- Saving Knowledge for later spells. Later spells are the expensive ones. Knowledge spent at tome three buys four times what it buys at tome eight.
- Forgetting the tome count. Points and count are separate requirements. Eight points with six tomes is still locked out of tier V.
- Choosing the culture before the affinity. The culture supplies one or two of your six starting points; discovering it fights your tome plan is a faction-creation error you cannot fix mid-game.
- Treating +5 casting points as nothing. Every tome grants it regardless of tier, which is why a cheap tier I tome in your affinity is never a wasted pick.
For which culture to pair with all this, see the culture tier list — affinity point efficiency is the ranking axis there too. For three complete factions, see the build guide. If this is your first game, the beginner guide covers the opening turns, and the honest review covers the DLC question.
