Aim to Maim

Whether through study or practice, you have developed the skills to go beyond hurting an enemy. You have learned to break them.

Once per turn, before you make an attack with a weapon that you are proficient with, you can choose to have disadvantage on the attack roll. If that attack hits, your target suffers the weapon's normal damage and one of the following Maims of your choice. Certain creatures may be immune to certain Maims, for instance, a gelatinous cube doesn't have legs and probably cannot suffer a broken one. The DM has the final say on whether a creature suffers the adverse effects. The Maim lasts until the creature is restored to max hp.

• Broken leg - The target falls prone. Its speed is reduced by half and it has disadvantage on Dexterity (Acrobatics) checks and Dexterity saving throws.
• Broken hand - The target has disadvantage on attack rolls using its hands or weapons held in its hands.
• Broken arm - The target's carrying capacity is reduced by half and it has disadvantage on Strength checks and Strength saving throws.
• Blind eye - The target has disadvantage on perception checks and attack rolls on targets more than 60 feet away.
• Internal bleeding - The target suffers one level of Exhaustion.
• External bleeding - The target suffers 1d4 points of unavoidable bleeding damage at the start of each of its turns. This effect ends as soon as the creature receives at least 1 point of healing. The damage increases by 1d4 when you reach 5th level (2d4), 11th level (3d4), and 17th level (4d4).
• Concussion - The target has disadvantage on Constitution saving throws to maintain concentration on spells.