Boss Yo-kai

are powerful enemy Yo-kai which the player cannot befriend or recruit, and are typically stronger than most Yo-Kai the player has met up to that point.

Most of the chapters in the Yo-kai Watch video games end with a battle with one of these bosses, and they are registered in the last few pages of the Yo-kai Medallium, just after the Legend Pages; however, they are not assigned any true Rank or Tribe, with the Boss symbol being in place of a Tribe's.

Some of the Boss Yo-kai become befriendable in future games following their debut, giving them a Tribe and a Rank as well as a smaller, more compact form, which is not considered a Boss Yo-Kai. Some befriendable bosses belong to either the Shady tribe -due to most bosses being sneaky with evil or bad intensions- or the Tough tribe -due to their high defensive and offensive power-. Also almost all bosses have a negative inspiritment.

Medals
With the release of Yo-kai Watch Busters and the release of the DX Yo-kai Watch U Prototype, the Yo-kai bosses featured in the game were given B-medals. Like the other B-medals, their medals are black-framed, and their artwork features the Bosses in action.

However, there are some differences. Their medals don't play the traditional summoning music of any of the 10 Yo-kai Tribes when inserted into the DX Yo-kai Watch U, but merely an ominous electric guitar. In addition, Boss Yo-kai Medals do not have any tribe-affiliated insignias on them; rather, they have a slash going through them.

Yo-kai that have B medals

 * Slimamander
 * Eyedra
 * Gargaros
 * Ogralus
 * G Baban
 * Red J
 * Prison Breaker
 * Whismallow Man
 * Dame Dedtime
 * Demuncher
 * McKraken
 * Kabukiroid
 * Robonyan No. 28
 * Hi no Shin
 * Akamaneki
 * Shirokoma
 * Robonyan 3000
 * Akamaneki Gold
 * Shirokoma Gold
 * Pink Emperor

Trivia

 * In Yo-kai Watch 3, the bosses are no longer given numbers that continue from the befriendable/normal Yo-kai's Medallium number. Instead, the Boss Yo-kai numbering restarts the numbering system, and adds a "B" for "Boss" in prefix form to the number.
 * Despite befriendable bosses like Slimamander or SV Snaggerjag gaining friendlier-looking forms, their medals still showcase their boss forms, indicating that all Boss Yo-kai have regular Yo-kai Medals that are simply unseen and never granted to the player.