» Leveling up

The way the leveling-up system works is you start off at level 0 at the beginning of the game, and by getting thick blood then turning it into serum, personalities can be leveled up. Each serum made counts towards the number of serum required to level up a persona in a certain area; ie: power, speed, waver, critical. Note: Mask has 'range', and Kevin has 'invisibility'.

Thick blood is converted into serum via the TV which is located in all the Harman's rooms. Channel 'B' is where blood is given to the Mad Doctor who runs the blood through a machine that will process the thick blood into serum. Once that's done, you can purchase abilities for any persona.

Thick blood doesn't carry on to the next scenario though, so make sure to take all your thick blood to the blood doctor before you finish a stage. The maximum amount of thick blood you can hold at a time is 1000kj, then it'll all have to be made into serum before more can be collected. Each stage has a limit/cap on how much thick blood can be processed through the blood machine. You'll know when you've reached the maximum limit when the blood machine breaks and is out of order :p Breaking them isn't a bad thing though, as it means you've gotten the maximum amount of blood obtainable in that stage, so you should be all good to level up the Smiths. Just spend serum wisely is all, especially if you're in a tough spot and need a certain persona's ability leveled up.