Alcahest (SNES) - Final Boss and Ending

Time to defeat the god demon butterfly.
This was played on PRO difficulty, no passwords used.
This difficulty, enemies do more damage, and you cannot find the Chalice that restores life when you die.
Alcahest here starts with this tiny magician form encased by the big machine body. You can only hurt him when he splits up to show the magician form in the center. Save from a few exceptions, every time he does so, he'll shoot a barrage of fireballs, first aiming straight up for you, and then around himself, then closes.
That's your main window to attack him with anything you can. Note that the open parts of the robot don't have a hitbox that can hurt you.
Aside from this, the boss can also summon this vortex wave that will either force you up or down, or swirling to the center of the screen. He'll also alternate to a phase where he'll keep shooting homing energy balls and a big energy blast fired directly downwards from his position. You can defend against the pellets with your shield, but generally just stay away from him.
Lastly and most dangerous, Alcahest will chant a death spell and summon a bunch of Grim Reapers around the screen. This attack is UNAVOIDABLE unless you use the Wind Guardian Blade's spell, and if you don't do it, you'll easily lose like 6 life squares! And when he loses about half his HP, he'll become much faster.
You need to clear this phase before your MP is completely depleted, otherwise you can easily get killed by his death spell. What I like to do is, if he doesn't summon the vortex, to stay close to his sides facing him, with the Wind blade charged; defending against the first few shots and then releasing it to hit him, then getting a couple of sword attacks. Using Sirius here isn't bad because his weapon has a long range.
If he uses the vortex, you can switch to the Earth blade charged attack instead and stay mid range from him. During the death spell, after using the Wind Guardian Blade magic to become invincible, stay close to the boss and pick the Fire blade. During the spell animation, you can release the charged attack to damage him a lot!
The second phase, he'll turn into the butterfly form. His attacks change depending on the color of his wings; if it's purple, he'll summon fireballs that appear randomly and travel horizontally on the screen, and if it's rainbow and he has more than half HP, he'll charge himself up with electricity, fly to the top of the screen and rain lightning from his finger. He can also disappear and summon meteors that will fall somewhat close to your position.
When he loses half his HP, he'll become faster and the lightning attack will change to these 4 electric balls that will cast lightning bolts horizontally and vertically on the screen at random. This attack is really hard to avoid, so it's best to save as much SP as you can to use the princess' healing special in a pinch.
Strategy for this form is, Water Blade charged attack does the most damage up close, Earth Blade charged attack is a safe option. None of your partners can hurt the boss so the princess is the only one you should bother with, for her healing. Earth Guardian Blade magic is pretty good to hurt the boss, and the Wind Guardian Blade can be useful too, depending on how much MP you have left from the first phase. You can shield yourself from the fireballs, by the way.
If you sit on the END screen for a while, the game will start playing every single song in the game while the characters show up doing things. The animation with the two girls kicking the demon head will loop indefinitely - I cut the video short there because it was already long enough.
Alcahest
1993, HAL Laboratory / Squaresoft
Translation patch by F.H., 2002; Addendum patch by KingMike's Translations, 2014
All rights reserved to their respective creators.