[ShadowChemosh]

Originally Posted by daplunk

Hit Die - Page: 276
Tiny: d4
Small: d6
Medium: d8
Large: 410
Huge: d12
Gargantuan: d20

This is now working for the adjustment. In addition I created the procedure 5CSizeChg to wrap all the logic into a single place for doing size changes. Note these scripts DO NOT change equipment on a character. You would need to go one step further to get this to work for say Enlarge Person where the gear would need to increase...

In example to increase a characters size by one do the following script:
First/20000

    ~ Sizemod is the +/- change to character's size.
    var sizemod as number
    sizemod = 1
    Call 5CSizeChg

In addition I added the new procedure 5CSetSize which allows you to set a specific size to the character no matter what it's starting size is.

Example Script:
First/20000

    ~       Tiny: -2
    ~      Small: -1
    ~     Medium:  0
    ~      Large:  1
    ~       Huge:  2
    ~ Gargantuan:  3

    ~ sizetarget is the new characters size
    var sizetarget as number
    ~ Force our new size be Gargantuan
    sizemod = 3
    Call 5CSetSize

To give valid credit the above concepts where done by Mathias years ago for Pathfinder when we where working on spell adjustments. I have heavily changed them to match 5e logic.

Originally Posted by daplunk

Damage Output - Page: 277
Big monsters typically wield over sized weapons that deal extra dice of damage on a hit. Double the weapon dice if the creature is Large, triple the weapon dice if it's Huge, and quadruple the weapon dice if it's Gargantuan. For example, a Huge giant wielding an appropriately sized great axe deals 3d12 slashing damage (plus its Strength bonus), instead of the normal 1d12. A creature has disadvantage on attack rolls with a weapon that is sized for a larger attacker. You can rule that a weapon sized for an attacker two or more sizes larger is too big for the creature to use at all.

As far as I can figure out this only applies to Manufactured weapons NOT natural attacks. Which that logic seems to be in HL already and working.

I base this on the fact that I am playing around with a Bone Devil which is size large and its Natural Claw attacks only do 1d8 damage not 2d8 damage. But if put a battlaxe onto the Bone Devil the battle axe does 2d8 damage.