Grappler. The yakuza thug gains advantage on any grapple check.

Pack Tactics. The yakuza thug has advantage on attack rolls against a creature if at least one of the thug's allies is within 5 feet of the creature and the ally isn't incapacitated.

Street Brawler. The yakuza thug adds their proficiency bonus to attacks with improvised weapons.

Wakizashi (Shortsword). Melee Weapon Attack: +3 to hit, reach 5 ft., one target. Hit: 4 (1d6 + 1) piercing damage.

Iron Knuckles +1. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 5 (1d4 + 3) bludgeoning damage. If the target is a creature, the yakuza thug can attempt to grapple it as a bonus action.

Back Alley Tactics. Melee Weapon Attack: +3 to hit, reach 5 ft., one target. Hit: 3 (1d6) piercing damage. The yakuza thug makes a melee weapon attack with advantage against a creature it is currently grappling.

Smash and Grab. Whenever the yakuza thug hits a creature with an improvised weapon on their turn, they can use a bonus action to attempt to grapple the target.

Unarmed Strike. Melee Attack: +3 to hit, reach 5 ft., one target. Hit: 3 (1d4+1) bludgeoning damage.