Enemy stats by difficulty in WotR
Core adds zero through the ordinary enemy difficulty bonuses shown below. That does not make a creature's base ability scores its complete combat statistics: class levels, equipment, buffs and other features still contribute.
Compare the same enemy
The example is a 
Bear with challenge rating 4. These are additions from the ordinary enemy difficulty feature, not final attack or Armor Class totals.
| Preset | Ability scores | Attack bonus | Armor Class | Hit point multiplier |
|---|---|---|---|---|
| Story | −4 | −2 | −10 | ×0.4 |
| Casual | −4 | −2 | −2 | ×0.6 |
| Normal | 0 | 0 | −2 | ×0.8 |
| Daring | 0 | 0 | 0 | ×1 |
| Core | 0 | 0 | 0 | ×1 |
| Hard | +3 | +1 | +1 | ×1 |
| Unfair | +7 | +3 | +3 | ×1 |
An ability-score bonus is added to the score, not used to multiply it. The Bear's base Strength is 21; the +7 Unfair adjustment gives 28 before any other applicable modifiers. The resulting Strength modifier can affect attacks separately from the direct attack bonus in the table.
The Bear at Hard difficulty: base attributes beside the added bonuses.
Challenge rating changes the bonus
Hard and Unfair scale their ordinary enemy bonuses with challenge rating. A bonus measured on the Bear is not the value for every enemy. Open the creature's own bestiary page and compare presets there.
The direct Perception adjustment follows the attack-bonus column in this example. Saving throws and spell difficulty classes have their own calculations and must not be inferred from that column.
Hit points need a complete starting value
The hit point multiplier applies to the creature's maximum before the difficulty adjustment. The result is rounded down and cannot fall below 1. A missing maximum is not zero hit points, and a base Constitution score alone cannot supply it.
These bonuses describe ordinary enemies with the difficulty feature. Party members, army units and special stat-changing features require their own rules.
Core, Hard and Unfair are different rule combinations
The difficulty settings also control enemy numbers, incoming damage and additional behaviours. Hard keeps Core's direct incoming-damage multiplier while increasing enemy bonuses. Unfair increases both. For enemy spell saves, use the separate DC calculation.