The Reincarnation

The Reincarnation is a sword that is made by combining the Merrry Life and the Merry Death.

History
The Reincarnation made its deput in The Reincarnation (Battle of the Swords 2) in which everyone was fighting over the Merry Life and Merry Death when Dark Ness discovered the Reincarnation and told everyone about it. Using Palutena's soul and Nobody's soul to balance himself more stabely, Dark Pit, the closest person to perfect balance, took the Reincarnation for himself. He never did much with it since he felt no reason to use it.

In Ketchup and The Candy Store, Dark Pit goes insane because he is not perfectly balanced. In the end, he loses the Reincarnation and, temporarily, his memories.

In the future, more attempts are made to retrieve the two swords and make the Reincarnation, but none have succeeded.

Details
The Reincarnation is a huge sword. Half of it is brilliantly shining and retains many qualities of the Merry Life while the other is dull and like the Merry Death.

To get the Reincarnation, you must get the Merry Life and Merry Death, then cross the two above your head. The Reincarnation will then judge you as you are surrounded in black light. If you are a perfect 50-50 (in Light-Dark Scale), then the sword will accept you. If you are not, it may kill you. The farther from perfect you are, the more this will harm you. Dark Ness approximated that  it would take about a 2% overshare in light or dark for the Reincarnation to kill you.

Some ways exist to potentially disrupt the system. For example, the only person to every wield the sword in the show was Dark Pit. To help balance out himself (he was about a 49.9-50.1) he used the souls of Palutena and Nobody, the basic kings of dark and light, during his judging. The souls whent back to their owners afterwards. The sword, however only partially accepted him. Eventually, it drove him mad and even took his memory.

The Reincarnation gives you unlimited power and wisdom. With it, you can literally do anything. However, due to its mechanics, only a person who favors no side in any war, and would thus only use its powers for truly good things to all, the power is always placed upon the right hands.

Appearances
The Reincarnation (Battle of the Swords 2)

Ketchup

The Candy Store (Ketchup 2)

Re-Reincarnation (and Dark Balls) (Battle of the Swords 3)

Trivia

 * According to one of the show makers, they were originally planning for Embless to get the sword. Most normals like him were more light due to light ruling the planet, but Embless' studies in Dark Arts made him a 50-50. It is unknown whether they kept the idea of him being able to wield the Reincarnation, however.