Does a seal or Kai'sa's legend (which provide floating power resources) count as energy, or do you still need to exhaust a rune to play a card like Hex Ray?

Ruling: Seals provide only floating power (fury, order, mind, etc.) but do not count as energy. To play a card like Hex Ray, you still need to exhaust a rune even if you have a seal or Kai'sa's legend providing universal power to cover the power cost.

Nuances:

• Seals can cover the power cost portion of a card's requirements
• Universal power from sources like Kai'sa's legend works the same way as seals - it provides power but not energy
• Energy and power are distinct resources