For example a creature with 1 RI would be affected as follows:
One damage Inflicted = One HP Dmg Taken
Two damage Inflicted = One HP Dmg Taken
Three damage Inflicted = Two HP Dmg Taken, etc
A creature with three RI is affected like this:
One damage Inflicted = One HP Dmg Taken
Two damage Inflicted = One HP Dmg Taken
Three damage Inflicted = Two HP Dmg Taken
Four damage Inflicted = Two HP Dmg Taken
Five damage Inflicted = Three HP Dmg Taken
Six damage Inflicted = Three HP Dmg Taken
Seven damage Inflicted = Four HP Dmg Taken
Eight damage Inflicted = Five HP Dmg Taken