User blog comment:Hitsuji Mamoru/Servant Creation Room 2 : Guess of the Who/@comment-31726296-20170709231502/@comment-4802891-20170710050045

I had a doubt but I know who this is now : Caeneus/Caenis.

A late addition to the Calydonian Hunt myth, it explains the E rank. The Noble Phantasm is most likely the undestructible body Poseidon granted her when turning her into a man.