The Dungeon Master

This creature has all colours.
After you roll the dice, you may:
{2}{w}: Change the result of the roll to the maximum
{1}{b}: Change the result of the roll to the minimum
{x}{g}: Add +X to the result of the roll
(up to the maximum of the roll)
{x}{u}: Add -X to the result of the roll
(up to the minimum of the roll)
{r}: Reroll