Personality: selfish, all about no.1 will always prefer to avoid a fight (stealth kills are fine) The blade and armour act as a hivemind when together, 'listen to us' 'we think you should abandon them' etc. When a creature is killed by this weapon, a shadow is summoned on a roll of 20 on a d20 under the control of the blade (active only if the full set is attuned). ( if a source of the light cantrip enters this area it is dispelled) the weapon deals necrotic damage. The user is able to see 20ft darkness as if it were bright light, including all darkness emitted by this blade. If the dim light is emitted in darkness it is considered magical darkness. If this dim light is emitted in dim light it is instead darkness. Shadow blade: emits an aura of darkness, it casts dim light in a 20ft radius.
Possibly +2 to stealth/advantage on stealth rolls depending on lvl. The sentient element withdraws into its shell becoming much less talkative. If you are hit, this ability is suppressed until the end of the next long rest. Shadow armour: whilst in dim light or darkness you are considered under the effect of blur. Monstrous Compendium Vol 3: Minecraft Creatures