Base Class: Fighter
The user of this technique can mark their target's body with lines divided into tenths. If the user is able to strike one of these lines on exactly the seven-to-three ratio point, they deliver a critical hit to the subject. This allows them to deal significant damage on tougher adversaries and cleave weak opponent's in two in a single hit.
The lines don't have to measure up to the target's full length or wingspan. Their head, torso, biceps, and forearms are all among applicable limbs for division. This technique can be used on inanimate objects in addition to living beings.
Seven to Three Ratio
Beginning when you choose this archetype at 3rd level, When one of your attacks hits as a bonus action you can roll a d20 and if you score 10 or below the hit does regular damage but if you roll a 11 or above you get to add one additional damage dice, you can only apply this on one attack per turn.
Improved Ratio
Starting at 7th level, every time you use your Ratio Technique (Critical Hit) instead of rolling 1 additional damage dice on a 11 or above on your d20 you add 2 additional damage dice.
Ultimate Critical
Starting at 15th level, your weapon attacks score a critical hit on a roll of 17–20 but you can only use this twice per long rest.
Ratio Technique (Critical Hit)
At 18th level, when you successfully roll a 11 or above on your Seven to Three Ratio ability you can add +20 to your damage.
Master of the Seven to Three Ratio Technique
Starting at 18th level, Your first three hits you land are automatically critical hits and you can add one additional damage dice. If you deal over 40 damage in one hit you can lob of a limb of a creature you're attacking.