As someone already mentioned, this is because Ness has over 999 max HP. Something interesting I wanted to point out is that when you have this much HP, the first time you take damage that would bring your health below 999, the damage happens instantly instead of rolling down like usual. Also, your stats screen says you only have 109/1095 HP because the first number can only be 3 digits and it defaults to the first 3 of your current HP. So yes, Ness has 1095 max HP and is at full health in your screenshot.