Here's what I used the trick is slow the speed to x1 during the 4 kages and wait to see who has full the most health and use izanagi on them and hit hiruzen so he does the reaper seal

Here have a video showing what to do for it

https://youtu.be/deQqvUulNzc

if you still can't beat it then the only thing I can say is power and or get better ninja.