Cyanis' Tower - Spoilers
You need to get the Crystal Key from the Rainbow Dragon (Violet Mountain) to get past the magic door at 1n/0e on level one. 
If you stand around Cyanis for too long he'll attack you (though you can run away). Killing him will get you a Magic Triangle 
If you cast any heal spell 'Flesh Anew' or greater (near Cyanis), you will Heal Cyanis of his insanity. This also get's you a Magic Triangle. 
