Axis of Mortality is a cool new card, but triggers at the beginning of your upkeep. Means that you’ve typically broadcast it for a turn and people can choose not to attack, keeping life totals roughly level. But if you’re playing with life totals, there are a few cards that may come to mind.
Triskadekaphobia means that 13 life is just as deadly as 0, and with Axis, you can change which player is at 13 life before the ‘phobia triggers, simply by stacking abilities.
Tree of Redemption changes your life total, but you can then use it with the Axis to change an opponent’s total to 13.
Or use Tree of Perdition and change your opponent’s life total directly.
Doran, the Siege Tower features all of these colors, is great for protecting your life total, and sets you up for some fun Treefolk tribal.