Fighting Style: Thunderdome

You can drop into a wide stance and plant your feet firmly on the ground, Drawing in a deep breath and compressing your senses into an extreme sense of touch, you gain blindsense by feeling disturbances in the air, and tremorsense by feeling vibrations from the earth, 

your character cannot move, see, hear, smell, or maintain concentration on spells and will attack anything that enters within a 10-foot radius will be attacked instantly expending a reaction(this includes allies), the player must expend at least one reaction attack when this happens.

all attack actions, bonus actions, and every 20 feet of movement are converted into reactions, and you can expend a bonus action to exit this state when it is your turn again

you can tell an ally a command word that will force you to exit this state

attacks done with a slashing weapon will do an additional 1d4 +your proficiency bonus thunder damage, as they break the sound barrier, and you gain 4 armor class, you are also unaffected by advantage, disadvantage, and the effects of flanking