You can choose a fighting style for your Thrall from the list below. You may have a separate fighting style feature for your Host. But your Thrall may not take another.

• Defense. While your Thrall is wearing armor, they gain a +1 bonus to AC.
• Dueling. When your Thrall is wielding a melee weapon in one hand and no other weapons, they gain a +2 bonus to damage rolls with that weapon.
• Great Weapon Fighting. When your Thrall rolls a 1 or 2 on a damage die for an attack they make with a melee weapon that you are wielding with two hands, you can reroll the die and must use the new roll, even if the new roll is a 1 or a 2. The weapon must have the two-handed or versatile property for you to gain this benefit.
• Unarmed Fighting. Your Thrall's unarmed strikes can deal bludgeoning damage equal to 1d6 + your Thrall's Strength modifier. If they strike with two free hands, the d6 becomes a d8. When your Thrall successfully starts a grapple, they can deal 1d4 bludgeoning damage to the grappled creature. Until the grapple ends, they can also deal this damage to the creature whenever you hit it with a melee attack.
• Tunnel Fighter. As a bonus action, your Thrall can enter a defensive stance that lasts until the start of your next turn. While in their defensive stance, your Thrall can make opportunity attacks without using your reaction, and your Thrall can use your reaction to make a melee attack against a creature that moves more than 10 feet while within their reach.

Your Thrall gains another style at 5th tier.