dont think about it too hard hoyo's powerscaling has always been wack, destroying a planet isnt even that impressive here, keep in mind doomsday beasts are said to destroy planets easily and these are just a part of the antimatter legion, Emanators are waaay above that too.
Blade's flesh was recreated from the Emanator of Abundance. It doesn't matter what people do to him because at the end of the day he'll wake up like nothing happened via immortality granted by Yaoshi the Aeon of Abundance
Blade's recruitment was Sam and Kafka taking turns killing him a few times, then Sam restrained him while Kaf used spirit whisper to 'convince' him to come along with them. So it kind of makes sense he doesn't have fond memories.