Premise: Northern Kings was a Finnish symphonic metal cover supergroup, made up of four well known musicians: Jarkko Ahola from Teräsbetoni, ex-Dreamtale, Marco Hietala from Nightwish and Tarot, Tony Kakko from Sonata Arctica and Juha-Pekka Leppäluoto from Charon and Harmaja.
Hypothesis: Other members of Sonata Arctica joined Northern Kings before Tony Kakko