Dema, The storm king

Flying first strike
Dema, the storm king enters the battlefield tapped
and doesnt untap during its controllers next untap step
When Dema, enters the battlefield untap all lands
you control then search your library for Blue five Instant and/or sorcery cards and five White instant and/or sorcery cards exile those cards
{t} Pay {x}{x}{w/u}{u} you may cast X instant
and/or sorcery cards exiled with Dema,
without paying their mana cost