Burning Rampageis dropped byLambent Firein Crystal Caves, Avalon. He has a few cheats and requires a stone skeleton key to be accessed.
Catch of the Dayis dropped byTakanobu the Masterlessin Cave of Solitude, Mooshu. He also has a few cheats and requires a Wooden Skeleton Key to be accessed.
Ninja Pigsis dropped byKoto, In Mooshu. Specifically, he's in Cave of Solitude and possibly one of the only bosses on this list that doesn't cheat or requires a key for entrance.
The Death Tendril has the spell Sacred Charge . This boss is inside Castle Darkmoor requiring a Gold Skeleton Key. Also cheats.
Those are all the spells from boss drops to my knowledge. The others are as you know, available as recipes, drops from Loremaster or available from packs.
Burning Rampageis dropped byLambent Firein Crystal Caves, Avalon. He has a few cheats and requires a stone skeleton key to be accessed.
Catch of the Dayis dropped byTakanobu the Masterlessin Cave of Solitude, Mooshu. He also has a few cheats and requires a Wooden Skeleton Key to be accessed.
Ninja Pigsis dropped byKoto, In Mooshu. Specifically, he's in Cave of Solitude and possibly one of the only bosses on this list that doesn't cheat or requires a key for entrance.
The Death Tendril has the spell Sacred Charge . This boss is inside Castle Darkmoor requiring a Gold Skeleton Key. Also cheats.
Those are all the spells from boss drops to my knowledge. The others are as you know, available as recipes, drops from Loremaster or available from packs.
Besides Koto, there are two other Mooshu bosses who drop permanent spells. Both bosses are in the Shirataki temple instance and don't require a skeleton key.
You must defeat the first boss, Shoji, in order to obtain the key to unlock the gate in order to get to Zaneki who is the boss of the Air Shrine. To get to him, take a left at the brazier right after you open the gate
Shoji drops the Samoorai spell (balance) Zaneki drops the Goat Monk spell (life)
