Witch

Are Slayer pareos for powerful witches in combat? assuming a witch can burn her target, destroy with telekinesis, or even stop the heart or brain with a spell? buffy has faced a witch and also Dark Willow, but we haven't seen all that potential.

Would a witch full of dark magic have enough power to harm Glory? I remembered some episodes from season 5 where Glory and Willow fight, and also when Dark Willow was already full of dark magic fighting Buffy and I found it quite interesting, or even vampires? Could a witch in the Dark Willow state with all that dark magic and rage harm beings as powerful as a God like Glory? Or did Dark Willow just assume the proportions it did because of the script?

look, I know this thing is complex, but I don't remember seeing it in the bufyverse, only in another series that I find this topic interesting, can witches lose their magical powers if they become vampires in the buffyverse? Could they be both? Witch and Vampire or is it impossible? Or even unnatural witches like Willow who became one could happen? Or would she just turn into a regular vampire?

I have a quick question

More magic a witch uses more it will be draining but can a witch keep a spell going indefinitely if the energy is draining something like a immortal.

For example when willow cast the boundary spell could she have channel a vampire to keep the spell going and as vampire are technically immortal as long as the vampire alive and the witch doesn't undo the spell, the spell will constantly continue.

Please let me know your thoughts and let me know if I'm right or wrong please.