Only recently started to use this spell. It's amazing. I now run it x2. The best part is that it has no limit on distance between the two champs. In the last game playing UD/KF deck, I had Vothsair Ireguard with very little HP left far away in the field and not in my spell casting zone. I deployed Aspect of Life, cast on her Blood Exchange, then had her heal herself to full health in the next turn. Insta-heal for tons of HP and only 25 Nora. In general, you can use it on any less valuable unit to boost HP of a more valuable unit. Edit: In splits, there might be not enough room for x2, but in FF UD, I think x2 is a viable option.
Used to run it in all my ud bgs with the 60 health imp as my sacrifice, the imp also had a death nova so he was the perfect scape goat.
What is this 60 HP imp you are talking about? 2v2 99-Nora-cost Vothsair Ireguard has only 52. It's a joke. He is so squishy.
Altered Lemure, probably. Has like 55 hp with banner out or something. Should be auto, but people don't know how to analyze runes very well.
I made posts about Bane Shift and Blood Exchange, because, as a UD player, I was given to understand that our faction had no good cleanse and healing options. And I had had this misconception for 2.5 years until I recently tried to run these two runes. I feel like it's a big deal: this somewhat erroneous image that was and perhaps is still promoted about the UD faction. In fact, one of the main reasons I switched to playing UD/KF was that KF had Cleansing Emerald. But now I am considering playing FF UD again. I have no intention to post about every single UD rune in the forums, but these two, I think, deserve to be mentioned.
Lemure before his nerf had like 60 base health and 2 death novas I believe, granted this was a while ago but he was my blood exchange and masochist target. Lemure is still a boss and extremely cheap for his health/Nora ratio.