Sword of The Lord Commander

This strong, elegant longsword is razor sharp and does maximum damage when attacking objects. Additionally:
{1} Rolling an 18-19 is a critical success
{2} On a critical, roll again. If you roll a 19-20 the target's limb is lopped off
{3} Speaking a command word toggles bright light in a 10-foot radius and dim light another 10 feet
{4} +3 to hit, +3 to damage