Multiplayer action/adventure games with 4-player online support

Assassin's Creed IV: Black Flag

Players: 4 local, 0 online

Terraria

Players: 8 local, 0 online

Super Dungeon Bros

Players: 4 local, 0 online

Windward

Players: 4 local, 0 online

Portal Knights

Players: 4 local, 0 online

The Wild Eight

Players: 8 local, 0 online

Portal Knights

Players: 4 local, 0 online

No Man's Sky

Players: 32 local, 0 online

Half Dead 3

Players: 4 local, 0 online

Necropolis

Players: 4 local, 0 online

The Survivalists

Players: 4 local, 0 online

Monster Hunter 4 Ultimate

Players: 4 local, 3 online

Luigi's Mansion: Dark Moon

Players: 4 local, 3 online

Terraria

Players: 8 local, 360 online

Assassin's Creed IV: Black Flag

Players: 4 local, 360 online

The Binding of Isaac: Rebirth

Players: 4 local, 0 online

How to Survive 2

Players: 4 local, 0 online

Don't Starve Together

Players: 6 local, 0 online

Disney Infinity

Players: 4 local, 0 online

Armored Core V

Players: 5 local, 360 online

Assassin's Creed Unity

Players: 4 local, 0 online

A Valley Without Wind 2

Players: 8 local, 0 online

Armored Core V

Players: 5 local, 0 online

Disney Infinity

Players: 4 local, 0 online

A Valley Without Wind

Players: 16 local, 0 online