The TRUE Knife.

The TRUE Knife Is one of the most powerful items to exist. While it is owned by User1204, they can also choose Charas they find worthy. Only another user or a worthy Chara can lift it, unless the lifter has the intent of giving it to a worthy Chara, and if they change their mind, the knife will fall out of their hand. Also, if the user of the knife wants to, they can let certain people pick it up.
Users-
User1204: The person who created, and has control currently.
Redemption Chara: First to get it.
CF Chara: Earned it.
DoFT: Used it to create the GenoKnife.
Nightmare: Breifly used it to kill someone who kidnapped Dream.
Mercy: Briefly had it before swapping ownership with FailTale Chara.
FailTale Chara: had absolute control over it.
Fresh: Somehow Fresh got it.