Size Bonus Multiplier is a special modifier given to characters of Size 2 or larger, the damage or healing dealt or taken is multiplied by their Size-Rating. They may also gain modifiers to other stats, and increase the number of bonus dice they roll. This multiplier can also be used by smaller characters whenever they score a Critical (Rolling 12 on a d12) using their Versatile Bonus to gain Size Bonus Damage, or through an Equipment or Metaphor effect. Some effects can also reduce this multiplier.
Size Bonus Modifier
The Size Bonus Multiplier is applied to the attacks and abilities of a character who is Size 2 or larger, or Size Tiny or smaller. Damage and Healing is multiplied by this value, other effects may also scale but only linearly (1, 2, 3, 4...etc). Size increases the number of dice rolled in dice bonuses, but only one per Size above 1. "A Size 4 creature deals four times more damage or healing with their attacks and abilities, and may gain a +4 bonus to other things which are affected by Size. If the creature has dice bonuses, they may roll three additional die when prompted."
Gaining Size Bonus Damage
To deal Size Bonus Damage as a non-Large creature, the character must score a Critical Hit by rolling a 12 on a d12 during an Attack roll. They can use the result of the exploded Meta-die's Versatile Bonus to declare a precision attack against a giant-sized foe. The attack is treated as being a Size equal to that die's result, but only up to the target's actual Size-Rating. Another way to deal Size Damage is through the enhancements of Equipment or through Metaphors. If a piece of equipment specifically treats its damage as being a certain Size larger to bigger foes, then its damage is multiplied, or increased by 100% for each rank of the enhancement. If conditions such as requiring to beat the target's Deflection need to be met before the bonus can trigger, the character must meet the condition before the damage can be modified.
Damage Limits
The Size Damage bonus can only multiply damage up to the target's Size Rating, and if the attacker is bigger than Size 1, then the maximum bonus is lowered equal to the difference between the two combatants. No matter how high the Size Bonus Multiplier is, a Size 1 Human can't deal more than x4 damage against a Size 4 Giant. And if a Size 2 Half-Giant attacks the same foe, they wouldn't be able to deal more than +200% damage due to the difference in their sizes. If two Giants of equal size fight, neither can gain a Size Damage bonus against the other.
Size Bonus Reduction
Because Giant creatures can deal lethal amounts of damage, there is an counterpart to Size Bonus Modifiers known as Size Bonus Reduction. A character who has, or is under the effects of this mechanic reduces an opponent's Size Bonus to a lower value, to a minimum of the user's own Size-Rating. Resistance A character with Size/Crush Resistance treats a larger creature's attacks and abilities as if they were half their Size-Rating, rounded down. If different sources give Resistance, subsequent stacks round up. Reduction X A character with Size/Crush Reduction treats a larger creature's attacks and abilities as if they were a fixed number of Sizes smaller. X denotes the number of Sizes reduced. Reduction can stack with Resistance, and if it does, Resistance is calculated before Reduction (to a minimum of 1).
Smaller Creatures
To determine the multipliers for creatures smaller than 1 (Medium):
| Size Category | Body Scale | Damage Mult | Size Damage required versus Medium |
| Small | 1/2th | 1x | - |
| Tiny | 1/4th | 0.5x | 2 |
| Diminutive | 1/8th | 0.25x | 4 |
| Fine | 1/16th | 0.125x | 8 |