Having a high damage to health ratio is common but not remotely essential, while people would consider having stamina much more important for the character of the genre because it introduces resource management. Another common example of resource management is having a heal with a limited number of uses that is restored at checkpoints. There's also usually a mechanic where when certain conditions are met, you can go to the enemy and do a much stronger attack with a canned joint animation between attacker and recipient (backstabbing and whatever the other one is called in DS are like this).

There are also other structural aspects of the game outside of the immediate combat, like the existence of those checkpoints that restore health and certain resources, certain elements of the world design (centered on shortcuts and unlocking doors, usually), the bloodstained mechanic, the soapstone mechanics for letting players leave each other messages, and a few other things.