https://www.polygon.com/nintendo-switch/2018/8/8/17664120/rathalos-shovel-knight-super-smash-bros-ultimate-assist-trophies

Part of the excitement in every new Super Smash Bros. game is the massive number of characters that can show up through the assist trophies. These could be side characters related to fighters on the main roster, or from different games entirely.

Each new Smash game has added plenty of new characters to help out during battles and Ultimate is no exception. During today’s Smash Bros. themed Nintendo Direct, the company announced over 20 new characters that will be joining the game as assist trophies