Shin Megami Tensei IV gets rid of random battles. The Symbol Encounter system puts demons on the field. Strike an enemy and you’ll get a first strike when the battle begins.

Like other Shin Megami Tensei titles you can talk to demons and invite them to your party. Shin Megami Tensei IV uses the press turn system from Shin Megami Tensei: Nocturne that rewards players that exploit enemy weaknesses with extra turns.

Demon fusing is back too. You can combine demons to make more powerful ones.

Tokyo is overrun by demons in Shin Megami Tensei IV. The protagonist and Samurai from East Mikado are sent here to protect the city. Atlus specifically mentions a battles between "law and chaos" and "god and demons" will take place here.

East Mikado… year 1492. When people become 18 years old they go through the Gauntlet Ritual to become samurai. Samurai are armed with a demon summoning program and hunt demons in secret. Only a few people know that demons exist in the world.

How do these two worlds connect?