[TOMT] [movie] 80-90s fantasy kid's movie with a brutal death scene

Hello friends! As usual we have another 90s movie question. I remember watching this movie in 4th grade which was the 2000-2001 school year for me, so the movie is from that time or before. I think the main character is a kid from the "normal" world who somehow ends up in some kind of medieval/fantasy world. The only real detail I remember, as it was quite traumatizing, is that there is a character who I think is supposed to be the kind of mentor/guide to the kid, and he is killed by having a sword go straight through his head. I believe the character was an older man with long white hair and he might have been Asian. Any ideas?