Summon elemental(summon creature).
Summons one creature to fight for you. it would use Principle of Element(80)+Principle of Imagination(?)+Principle of Light(?)(to summon some healing or protecting creature) or Principle of Darkness(?)(to summon offensive creature). can be used only if you don't have enough creatures or half of creatures necessary for ritual vitality is below 5%.
As spells name points - principle of element i added to summon elemental, but it can be changed to other principle(cyclity or enthropy or syntropy) to summon other creatures.
But i dunno if this is possible. You