What would be a progession system for Mara Straint (DH core book) if one got infected until final stage is reached?

OK. I got it. If you are infected, then it is final stage like in DH book. Looking into Harlock Legacy adventure, a victim looks cold, is going insane, veeps blood, hears buzzing when using powers.

now, how to escape such terrible fate? One thing, Holocoust? it can kill deamons. So with good enough WP you can generate around 6d10 damage and if infested PC has something like Larval Form, then it can be killed in single hit.

Fate Power "Purge the Unclean" from the Inquisitor's Handbook (p.51) can work.