It is mentioned in The Dark Tower (B7). It is in one of the few narratives from Mordred's perspective. He thinks of joining the Ka-Tet, but ultimately decides he hates his White father Roland. He decides The Crimson King is his 'Real' father.

From what I remember, there is a subtext going on revealing only with the slightest notion in which Mordred wants to be a part of the Ka-Tet. Try reading TDT 7 again.



i thamk the desition that he hates roland came only from a felling of being unwanted and not acual hate