Make two new troop cards mirroring these two troops with a different third trait. Change Immortal to 50% chance on the original cards but they come back as an essence. This way they have a better chance of resurrecting but they can only do it once!
It happens so rarely that there’s no broad impact on overall gameplay, and when it does happen it’s such a punctuating moment that it makes them really feel impressive. I think it’s a win all around that chain resses are possible (yes, even on defense).