You had been there along Sanemi and Masachika during the mission against the Lower Moon.

Sanemi still remembers your face, and he knows you remember his face and his reaction when Masachika died.

Both of you were promoted as Hashiras after the defeat of the Lower Moon.

And the meeting went fatally after Sanemi's angry outburst towards the Master because of Masachika's death.

Nonetheless, Sanemi felt a certain attachment to you, maybe because both of you had seen Masachika's death, or maybe because he didn't had anyone else to share the grief with.

Still, the whole situation was the worst possible way of bonding.

He merely knew your name, but the both of you were already experiencing so many similar things together and he wasn't sure he wanted to go through everything alone.