Complex sentence: Titus chastises Leandros for his narrowmindedness, claims he knows nothing about why he is resistant to Chaos and his intentions are noble, but still willingly goes with Inquisitor Thrax rather than creating a dishonorable scene and staining the good name of the Ultramarines.
Split into simpler sentences: Titus chastises Leandros for his narrow mindedness and claims he knows nothing about why he is resistant to Chaos and that his intentions are noble. He still willingly goes with Inquisitor Thrax rather than creating a dishonorable scene staining the good name of the Ultramarines.