He speaks of your prideful failures; a lost life lost.
Everdred & The Final Flying Man
In the unusual circumstance where you rescue Paula from the Carpainter, but she's dead when you bring her back to Everdred, he tells you, "I heard that you've been pretty proud of yourself since you saved Paula's life. Think about it, you didn't actually save her. Come back when you've accomplished something."
The Final Flying Man answer surprised me, but it seems to fit quite well with the riddle. When all you have left is one last Flying Man, he tells you, "Of course, we're your courage. But we warned you not to treat us like trash! Didn't you get it?! This isn't courage, it's desperation. If you don't understand look it up in the dictionary. Okay? My name's The Final Flying Man." As the Flying Men are defeated, tombstones are left with descriptions of them on it. However as you progressively lose them, their descriptions become shorter and shorter until eventually Ness cannot recall who they even were. The Final Flying Man scolded you for your misguided failures, and his memory died along with him. All that is left is simply "Tombstone".