First, this mod makes enemies drop 'health pickup' hearts, which heal the player on contact if needed. If you touch them at full health, they become an item for healing later, and can be crafted into stronger ersions. Drops can be changed in the config file
Second, this mod allows you to customize the players initial starting health, so you can start at 3, 5, or even 20 hearts to begin with
By default you still get 10 hearts, but in your single player world or modpack you can set this to something low for a challenge, or much more to soak up damage
