I have defined this function to print text slowly:
import sys
from time import sleep
def print_slow(s):
for letter in s:
sys.stdout.write(letter)
print_slow() returns None which you pass to the input() function. That function uses that argument as the prompt to show the user when asking for input:
>>> input(None)
None
None is the default return value of any function, unless you give it an explicit return value with a return statement, which your function lacks.
Call input() separately, you don't have to give it a prompt to print:
print_slow("\n\nWhat is your name? (EASTER EGG CODE: \"blackbeard\")\n>>")
s_name = input()
The str() call is redundant, in Python 3, input() returns a string, always.