I have died twice now and the rot on my arm doesn't appear to have grown and I was able to keep playing. At the start, when I first died, it said if I made too many mistakes the rot would travel to Senua's head and the game would be over. What is the deal with it? How many mistakes does it take for it to trigger the perma death. I have been backing up my gamesave to the cloud just to be safe, but It would be good to know what it takes to make the permadeath trigger and what it takes to actually get the rot to travel to Senuas head
I havn't heard of anyone actually loosing their game save yet due to the permadeath, but I would play it safe anyway. Someone has made a video where they died 50 times and the permadeath never kicked in. However, the rot did travel up her arm slightly.
Other people have found that the rot traveled as far as the shoulder. It seems that the rot will only travel so far at a certain point. So in the video above, if you die a certain amount of times in 1 area, the rot on your arm will progress a fixed amount. Any additional deaths after the fixed amount is reached will not make the rot progress any further. I would say that if you died 50 times, stretched out over the entire game, the outcome might be a lot different.
While we don't fully know how the permadeath in Hellblade works yet, I would definitely play on the safe side. If it isn't too much trouble, back up your game save. You can definitely die a few times and not trigger the permadeath so there is no need to get stressed over a single death or anything like that, but be careful anyway.