Thread:Ain Soph Aur/@comment-13797053-20140513194011/@comment-5838340-20140604233934

A prerequisite is a required prior condition. If something is required in advance of something else, like if you have to take a beginning Spanish class before signing up for Spanish II, then it’s a prerequisite.

The character doesn't have Medical Ninjutsu under it's bio nor states it anywhere else; this needs to be done first before claiming it.

Now about Senjutsu being a requirement? You didn't missed the part where Hashirama's face on Madara's body magically took in Senjutsu chakras and thus let the man go into Sennin Modo? It's right there in the link you gave me.