Did you notice the hero player’s party in the extended Shin Megami Tensei IV trailer? He has three really powerful demons Beelzebub, Surt, and Black Rider. No wonder he makes mince meat out of Girimehkala.
Atlus revealed more demons than those. There’s a fight with Titan and Kelpie shown too where are easily defeated. Did you notice which demons the protagonist had?
Balor, Hokuto Seikun, and Abaddon.
Another battle shows Dantalian Bifrons, Ose, Halphas, and
a demon from Strange Journey that I can’t recall Melchom (thanks Tommy Lee!).
Hua Po, Genbu, and Jack Frost are seen in this battle.
In the battle against the Frost family – King Frost, Black Frost, Jack Frost, and Frost Ace – the protagonist had Susano-o, Apsu, and Black Rider (again).
Makami and Momunofu are seen during demon fusion. The hero also has Kikuri-Hime and Yatagarasu in his party.
We also noticed Murmur, Kresnik, and Tenkai (not pictured) which appears to be a brand new demon.
Kougasa Burou is a new demon too. Many of the demons Atlus revealed in the trailer like Balor and Apsu are from Devil Summoner: Soul Hackers, the 3DS Megaten game that included a trailer for Shin Megami Tensei IV.