"A giant guardian that's against evil. His power's effect is demostrated for the first time when paired with Akamaneki. Recent grotesques have takenplace recently in the human world, since this power has been lost."
Shirokoma (Japanese: 白古魔,Shirokoma) is a secret Boss Yo-kai in Yo-kai Watch Busters. You can challenge him in Red Cat Team by going to the YBK hall and put stickers (you get from playing with someone with the same version or street passing) on Akamaneki. You can only put 100 stickers a day, however. Also, you have to play with 2 or more players that has Red Cat Team too.
Shirokoma resembles a Komainu with white skin and light gray beard and eyebrows. As with normal Komainu, he has protuding fangs which are golden in color. He wears a bronze colored, finely gold crafted chest piece and silver bracelets. He carries a golden egg with a strange-looking single eye. For some reason he is surrounded by four orange Hitodama Flames.
Shirokoma strongly resembles a komainu, a statue that is said to guard shrines by warding off bad spirits. They always come in pairs.
It is possible that it is the Yo-kai Form of the Keymaster; Vinz Clortho from Ghostbusters.