Mr. Ishtar is the father of Marik Ishtar and the adoptive father of Rishid Ishtar. He is a minor antagonist in Yu-Gi-Oh. Despite only being seen in flashbacks, he is considered an important antagonist, as his actions were responsible for the creation of Dark Marik, the Bigger Bad of the Battle City arc.
Mr. Ishtar and his wife adopted Rishid after he was abandoned as a baby. Mrs. Ishtar sadly died giving birth to Marik. Her husband showed no sadness about this because he now had an heir. He would later go on to sadistically carve up his son's back as an ancient ritual, and the anger and hate Marik felt towards his father would eventually form Dark Marik. When Marik and his sister Ishizu snuck out (which was strictly forbidden to do) and his father found out, he was about to banish Rishid, when Dark Marik took over Marik's body, took the Millennium Rod and stabbed Marik's father to death (while in the 4Kids version, he sent his father to the Shadow Realm though there is little difference between death and being banished to the Shadow Realm).
- Due to the graphic nature of Mr. Ishtar's crimes, he was severely toned down in the anime.
- Mr. Ishtar is responsible for the creation of Dark Marik because had he not tortured his son, Dark Marik would have never been created and he might still be alive. This makes him the Greater Scope Villain of the Battle City arc.
- Mr. Ishtar and Marik look exactly alike (except for the beard).