Seiyū: Masami Kikuchi (English dub: Crispin Freeman)
Sieg Hart (, Jiku Harudo) is a Defender of Time from Mildea and an elemental master, he was originally out to kill Elie, but eventually joined Haru on his quest after realizing that Elie needs to be saved. He was originally working with Demon Card (he was plotting to kill King) but left after trying to kill Elie. He helps uncover Elie's memories.

Source: Wikipedia