The Chant

Magister difficulty isn't really as bad as it sounds. I combo'ed this one with "beating the game under 4 hours" and for "not killing any Cultist." Which again doesn't sound as bad as it is. Your main objective while going for this as follows and I'll list what I did for this too.

1. Almost every section you can avoid killing enemies unless the objective specially says you must kill X enemy to progress the chapter.
2. Dodge and laying traps with salt will be your best friend. Many objectives can be completed by simply slowing/stunning enemies and then interacting with the objective.
3. Heavy attacks with oil will often destroy many bosses. Use this to quickly deal with most of your major encounters. The only one that really gave me trouble was at the lighthouse, and in that case make sure you use your "swarm destroying" weapon when applicable.
4. Make sure you spend a bit of time to upgrade your base stats and the effectiveness of your items. The ability to take less damage from attacks is rather nice too.

Last my biggest advice is to avoid as much combat as possible, you are like a weak baby in this mode and will die from 2-3 hits easy. Kite enemies around when possible or just flat out run. I found this best to do after I completed the game at least once as I knew the routes pretty well and what I needed to fight/not fight.