Combat Grapple Mastery

Preferring to get up close and personal, you've developed the skills necessary to dominate the fight close-quarters grappling under combat conditions. You gain the following benefits:

• You can use a Dexterity (Acrobatics) check contested by a check of the target's choice Strength (Athletics) or Dexterity (Acrobatics) in place of the regular Strength (Athletics) checks to grapple or affect a grappled creature.
• You have advantage on attack rolls against a creature you are grappling.
• You can use your attack action to try to pin a creature grappled by you. To do so, make another grapple check. If you succeed, you and the creature are both restrained until the grapple ends.
• You can use another attack action to lock up the creature's joints with your superior knowledge of this fighting stile. To do so, make another grapple check with advantage. If you succeed, you and the creature are both incapacitated. Once this is done, and on subsequent turns, you can use your bonus action to inflict pain twisting the target's joints (unarmed attack) or attempt to choke them out.
• Choking requires the target to make a Constitution check DC = 10 + Proficiency + your Dexterity Modifier. The target can make a number of attempts equal to half its Constitution Modifier, rounded up, minimum of 1.
• A choked creature that fails its checks falls unconscious. It remains at whatever its current HP count was. The creature remains unconscious for 1d12 rounds or until it takes damage or an creature uses an action to wake it up.
• If the target fails any of its grapple checks by 5 or more, the following condition does not apply to you. In turn, if it fails the first check by 5 or more, but the second one by less, you are restrained rather than incapacitated.