Allahowl, Blade of the Twin Wolfwarriors

weapon (twinblade), legendary (requires attunement)
Twinblades are ornate staves with long blades. Attacks with this blade deal 2d6 slashing damage. It is considered a heavy, two-handed weapon.
You gain a +3 bonus to attack and damage rolls made with this magic weapon. It has the following additional properties:

• Special. If you attack with this twinblade as part of the Attack action on your turn, you can use a bonus action immediately after to make a melee attack with it. This attack deals 1d4 slashing damage on a hit.
• Twinwolf Blood. While holding this weapon, as a reaction to taking damage from any attack, you can choose a willing creature within 30 feet of you to take half of that damage instead, while you take the other half. In addition, as a reaction to seeing a creature within 30 feet of you take damage, you can choose to take half of their damage, while they takes the other half.
• Oath of Brotherhood. While holding this weapon, once per day, you can choose one willing creature within 5 feet of you. Until your next long rest, while within 60 feet of each other, you and that creature have a +3 to your AC, +3 to your Wisdom (Perception) checks and Wisdom saving throws and you may use each other's senses at will (no action required).
• Speech of Allahowl. Within Allahowl rests not only the Grove, but also the Twin Wolfwarriors. From time to time, the voices of either the Grove or the Wolfwarriors can be heard by its wielder. The Grove will always advise the wielder to break the blade or do evil deeds, while the Wolfwarriors will always argue for lawfulness and honor