Complex sentence: During the events of "Prelude to Dune", the head of the House is Archduke Armand Ecaz; at this time, House Ecaz is in kanly, or vendetta, with House Moritani.
Split into simpler sentences: During the events of "Prelude to Dune", the head of the House is Archduke Armand Ecaz. At this time, House Ecaz was in kanly, or vendetta, with House Moritani.