The song Mr. Ego is about Michael Kiske.
Kai Hansen wrote the song "I Want Out" because he wanted out from Helloween. One year later he left the band.
The Keeper of the Seven Keys was originally one double album but the music company divided it into two separate albums.
The first Live album of Helloween had several names. "Live In The U.K." in Europe, "I Want Out - Live" in the U.S. and "Keepers Live" in Japan - which by many fans were assumed to be different albums. This was done by the record company to win extra money from the sales.
The monster shown on the cover of the album Walls Of Jericho never stuck around to be a Helloween trademark but rather eventually became the mascot for Gamma Ray, a project of former Helloween lead man Kai Hansen.