Otto Dantz is the son of a Nazi war criminal. He ascended to the leadership of the Neo-Nazi group, The Knights of October. The Knights of October are described by Hellboy as "Equivalent to the Knights of Malta... or the Templars. After the First World War they swore they'd make Germany great again and win the next war."
In Batman / Hellboy / Starman, Otto Dantz has the Knights of October kidnap Ted Knight in order coerce him into raising an Elder God which the Knights will then use to take over the world.