From Bulbanews, your community Pokémon newspaper.
Revealed alongside game release
Two more Ultra Beasts, both codenamed UB-04, have been revealed by the official Pokémon Sun and Moon site. These are the Ultra Beasts that were revealed in this month’s CoroCoro Comic. The official Japanese Pokémon YouTube channel also released a promotion video along with this reveal.
These reveals coincide with the official release of Pokémon Sun and Moon worldwide (except in Europe). For further details on these Ultra Beasts, please see the Bulbapedia pages for UB-04 Blade and UB-04 Blaster.