How do you unlock all online mortal kombat karnage characters?

To unlock all characters in Mortal Kombat: Karnage, you typically need to complete specific challenges, achievements, or progress through the game's various modes, such as the story or towers. Some characters may also be available through in-game currency or by completing events. Always check for any updates or events that might offer additional characters. For detailed instructions, refer to the game's official guide or community forums.