Head of Sonic Team Explains the Difference Between Chao and Sonic Frontiers' Kocos

gamerant.com:

Sonic Frontiers may be the most intriguing Sonic game in the last decade. Not only is it the hedgehog's first venture into being open world, but it's kept fans in the dark for over a year in regard to its plot and full gameplay loop. Some players couldn't parse what they truly thought of the game until the Gamescom release date trailer was revealed. As Sega revealed small pieces of this curious new title over time, players noticed small rock creatures in gameplay footage that would eventually be revealed to be the Kocos.

Many fans were of the opinion that these critters would be a replacement for the Chao from the Sonic Adventure titles. Due to how popular this sentiment is, Sonic fan-site The Sonic Stadium asked the head of Sonic Team, Takashi Iizuka, if fans could consider the Kocos as «the new Chao» at Gamescom. His answer was that they aren't a replacement for the fan-favorite pets because Kocos and Chao function in different ways.

Sonic Team Leader Explains Sonic Frontiers' Use of Old Level Designs

According to Iizuka, Chao are little creatures that players can «grow and nurture and play around with,» while the Kocos are tied to special abilities and unlockables that assist the player the further they go into Sonic Frontiers. The rock critters not only help the player progress, but the leader of Sonic Team also said that they play an important role in the game's story, and that saying too much will «spoil the mystery.»

This is a first for the smaller companions that have been featured in previous Sonic games as none of them have played a huge role in the story before. Even the Wisps, the new alien creatures found in Sonic Colors, weren't treated with such secrecy despite how they were the new friends Sonic had to save