So in case anyone is wondering the spelled failed because the target birch was not dead.
Because there was no target of the spell it broke the circle and rebounded into the caster and btw rebounded spells have a high chance of 1 of 2 things happening.
1. the rebound target dies.
2. the rebound target can NEVER CAST MAGIC AGAIN.
This was from the WN and it could possibly be a mistranslation but that's what i got from it.
I guess they didn't have a way of knowing he was alive at the time, but damn did it have such drastic consequences. I guess not all Bichir's decisions panned out for the better, good good, such an organic story flow