Living Weapon in Nioh is a power up attack or series of power up attacks you can use that is based upon which Guardian Spirit you have. You can use Living Weapon when your meter on the upper left-hand side of the screen is slowly flashing by pressing △ + O at the same time. Your living weapon meter will fill when you get amrita for killing or staggering enemies. Note that using Soul Gems will also fill the Amrita Gauge, as well as replenish the meter while Living Weapon is in use.
Living Weapon Information
When using a Living Weapon, it is important to note that your stance is locked to Mid-Stance, and cannot be changed until the Living Weapon fades. The Health and Ki Gauges are replaced with the Living Weapon Gauge, which decreases slowly over time, or whenever you would expend Ki or take Health damage (though no Ki or Health is actually lost during Living Weapon). Depending on the element of your Guardian Spirit, your attacks will become charged with an element, as well as deal increased base damage.
Any combos or skills you know for your equipped weapon cannot be used in Living Weapon mode, but boosts on your equipped armor and weapons will also affect your Living Weapon damage, making it a potent method of dealing burst damage to tough enemies, especially if you stack Elemental Damage buffs. Any Onmyo Magic or Ninjutsu also affect Living Weapon.