This puzzle comes from the novylen minecraft server. The word “novylen” itself might be a clue or a key.
The puzzle itself is:
I am a word of six letters,
The start pull wagons,
My last two letters are the opposite of out,
Put me all together, and I'm what you can't live without.
Y ko o hwpn ix uzkfjrpi
Lk jtwddr uk gur oqf djimlq
Mj pbzz gfwfotdsjqi vt yjg
Jkx qtj yqq jcu vjg crrn yjqtkpi Yjcvcp dn
TDAE AE AN FY ABLPGY
def5020013c86461ba8b2cc5cba3ad7bd00a0b69a2d8de6d3737b44841ac1f7967e1897af6b493fc44598982d14464a6cdf52dc8a6ba3c4331e24a4a2d47bdabe6100ed8fe8c66fe83624669b7cfc870d93abfb70e87401b4e804cd5d8b8aae59f3c51569ac75fcc572129
eUhzWEd1YzhLRURUZ3VkVnVtR3NnZlVlMSs4ZXViSkp6YW10UVhiUDRxST06OjU5d3S9mu93CTj9MHoIl8A=
The answer to the first section is “oxygen”. This has been confirmed by the creator of the puzzle.
We have not been able to progress further. One hypothesis is that each section needs to use the answer of the previous section to be solved. As such we tried various ciphers like caesar, vigener on the next section but with no luck. Oxygen having the atomic number 8 might help, but we were unable to use that information to decipher the second part.
The last line looks like base64 but it doesn’t seem to be.