There will be no other king except bitcoin and this is facts. There is no other coin out there to challenge the bitcoin throne so I say let's stop dreaming and accept the reality.
As of now, i can say that bitcoin is still on the crown of being the king of all digital currency. However, we could not say that it will be forever because maybe in the future there will be another technology that has a better feature than bitcoin. But for now bitcoin has still the highest value of all the coins. Goodluck to all of us.