Samus Aran on 04 February 2015
"Online matches will be all human players, no CPU, potentially meaning some waiting for lobbies to fill up. 4 vs 4 is also the only option online, to avoid the player base being split up."
http://www.nintendolife.com/news/2015/02/famitsu_article_reportedly_inks_out_more_splatoon_details
This is what Nintendo Life says. Maybe there will be more modes, but all of them are 4 vs. 4?
