Interesting idea.
What happens if you have 2 kings in play (Kings A and B)? Both anointed several creatures (A1, A2, A3, B1 and B2) . When King A dies does the damage also applies to creatures B1 and B2. The wording says it should but it might be better (more strategic) if it was separated. And then if both kings are killed, how much damage is dealt to each creature it should be 10 with the present wording but again ... a slight modification might be nice. I don't know about the coding though.
Concerning the name:
Unupped: Dark king, fine. I would maybe have chosen something more religious (like dark priest or Guru) but King is fine.
Upped: Evil Monarch. Meh. First, calling a creature evil because it lives in the shadow is a bit too simplistic IMO and second, Monarch is a generic name which does not really fit here. If you stay with the king theme, then I would go for Dark Emperor. It could also be Prince and King, etc. ...
Concerning the balance:
I find the un-upped perfect as it is. You can use it as a mass-buffer or as a twisted CC (If you kill my King, all my dunes will die but your dragon will too).
For the upped version the strategy is kind of altered. Give your opponent's creature a +3|+3 and the death of the king might not kill it (even a ruby dragon a shrieker or a GotP). Then you loose the main edge of the card. In this case, Patch's idea might be interesting: if the king dies applies -3|-5 (and -5|-7 upped). However, it might not be necessary. I would rather lower the ability cost of the monarch and keep the rest identical. Therefore it is simply better to have the upped card.
Concerning the ability: Should the Anoint ability stack or not? Should Anoint give more then +1/+1?
I would say if it stays at +1|+1 (even upped) then it should stack. That's why I thought the religious thing was thematically better (the more time you spend with your guru the more fervent you become).
However, being able to chain the blessings (+3|+3) would be bad.
