Fear
The only time Hashirama saw fear in Madara's eyes was the moment the other turned around and saw his little Brother fall. When he tried to make Madara agree to the peace treaty he inwardly hoped that the end of war would protect his friend from feeling more pain.
But Izuna made him refuse.
Many people began to call Madara a monster shortly after that day because he started fighting regardless of consequences. And when some asked themselves if there was anything he feared Hashirama was the only one who knew the truth.
Madara's only fear had already become reality.
Thanks to everyone for reading this third chapter. I hope you liked the drabble. Feedback is much appreciated!