New rune idea: An adaptive damage to defense health based rune.
This would likely be under the Resolve tree. What it does is that it changes from damage to defense as your health lowers, and vice versa.
Lets say that at 100% health you gain X amount of adaptive AD/AP. But as the health gets lower, the adaptive damage gets converted into adaptive defense, in other words, Armor and Magic resist based on what you receive more of (like Camille passive). Lets say that being under 20% health gives you no adaptive damage but full adaptive defense. The changes could be scaled every 20% to make it simpler. So at 80% health, you have mostly adaptive damage, but also a slight amount of adaptive defense. It would be a ratio. 100% health = 100% adaptive damage / 0% adaptive defense 80% health = 75% adaptive damage / 25% adaptive defense 60% health = 50% adaptive damage / 50% adaptive defense 40% health = 25% adaptive damage / 75% adaptive defense 20% health = 0% adaptive damage / 100% adaptive defense As you heal, the adaptive defense is converted back to adaptive damage