Why not Angel of Grace ? Unlimited entries from your citadel!

If you would like, I can post a link to my decklist that I built off of Frank Karsten's. Mine is an all in combo deck then looks to kill the OP on turn 5 or 6, and it consistently does that. Using cards like the new saheeli and top deck manipulation, the deck is very consistent.

driule Angel of Grace doesn't prevent loss of life, only damage unfortunately.

EchoScorch I would love that!

Bolas Citadel Combo The main issue with the deck is that it is a glass cannon - It either goes off or dies. While it can gain life to get past aggro, if they have a constant board state and you do not kill, you will die and control is a god awful matchup. After play testing your deck more it looks like a more midrangey deck that gums up the board is a better option.

The things that I am testing in your deck right now are either Domri, City Smasher or End-Raze Forerunners in order to give all of the creatures that you play on your turn haste in order for a turn five/six kill.

Edit - End-Raze Forerunners doesn't give haste, just vigilance and trample. So your options are the big domri, or Heroic Reinforcements , or Garna, the Bloodflame , or the new samut, all of which except for Samut are not castable on the manabase currently. I went ahead and made a version of your deck with tweaks to the colors and the cards - Here it is Green/Black Bolas's Citadel Combo - WAR.