Ruffian Feat

You have turned kicking people that are down into an art form. You gain the following benefits:

Prerequisite: 4th level

• Ability Score Increase. Increase your Strength, Dexterity, or Constitution by 1, to a maximum of 20.
• Painful Critical. When you score a critical hit with a melee weapon attack against a creature, it must make a Constitution saving throw or become blinded or dazed* until the start of your next turn. This does not affect undead, constructs, or other creatures that can feel no pain.
• Gain the Dirty Strike special ability (below).

Dirty Strike - Active Ability (Special)

• When you make a melee weapon attack, you can follow up with a dirty trick (a knee to the gut, handful of sand to eyes, etc). The creature must make a Constitution saving throw. On failure, they become your choice of blinded or dazed* (your choice) for 1 minute. The target can repeat its saving throw at the end of each of their turns. A creature can spend their action treating their condition to automatically pass the saving throw. Once you use this against a target once, they are ready for subsequent attempts and automatically pass saving throws against it.

Once you use this feature to successfully blind or daze a creature, you cannot use it again until you complete a short or long rest.
Source: KCLL, page 184

Active Martial Feat Save DC:

• Any time an active martial feat requires a saving throw, the DC is 8 + your Strength or Dexterity modifier (your choice) + your proficiency bonus.

*Dazed Condition

• A dazed creature can only do one of the following: move, take its action, or take a bonus action. It cannot take reactions.