Adelheid and his sister Rose reside on an airship called "Sky Noah". In The King of Fighters 2003, he would challenge fighters there at the behest of his sister. His story in The King of Fighters XI implies that he faced the Ikari Warriors Team and was defeated by them. He peacefully chats with Heidern and explains that he is only following his father's legacy. In his ending for the game, he seems to appear regretful for his actions and yells at his sister for insulting his opponents.
Role in Super Smash Sisters
Adelheid Bernstein like in the original KOF2003 is an NPC in Super Smash sisters. Like in KOF, he normally relies on kicks as normals. His Reppukyaku can come in handy in battle. He will also use his other specials form his KOF days. His hands can cut through his enemies skin. He can make a barrier to send projectiles back.