Strangler

You’ve developed the skills necessary to hold your own in close-quarters grappling and have understood the importance of breath in a battle. You gain the following benefits:

• You have advantage on grappling-checks.
• You can use another action to try to strangle a creature, provided your character knows how it breathes. To do so, make another grapple-check. If you succeed, the creature can re-roll athletics-checks each round to try to break free.
• You can cause 1d8+strengthmod worth of bludgeoning-damage when you have a creature in a strangle-hold, these attacks are made with advantage and considered unarmed strikes. If you roll a critical hit then the creature will be unable to breathe until the end of your next turn, regardless if it broke free or not.
• Creatures that are more than one size larger have to be successfully scaled before a grapple can be applied
• Some creatures that cannot feasibly be strangled with the body of the grappler alone will require an item to aid in the efforts. Which ones can and which ones can't is left to the DM's decision.