The Great Tree – Part 1
Fifth segment: Long and quite self-explanatory. Just conserve MP for Heal Light and watch out for the Shadows and the annoying Thanatos Poron who keeps abusing poison arrows. In the long tunnel portions, you need to be at the lowest elevation so the moving ball doesn’t flatten Keldy. Just keep moving if you are at max levels.
Sixth segment: Follow the unknown lady and beat up the materializing Shadows…
… wanna know who’s the final boss?
8-5: Thanatos Poron is your worst enemy apart from the regular Shadow demons. Always kill them first or run the hell away. Their arrows are almost always Poison-ready and they fire them with no start-up. This is a really long section so pace yourself and conserve MP only for Healing Light. Once you reach the cave sections, dodge the Boas if you’re already at max stats.
Final Boss: Medusa/Anise
Medusa is fully immune to Panic but the Blast and Frost Serpents aren’t. Their weaknesses are Undine/Frozen Saber and Salamander/Flaming Saber respectively. It is not recommended to strike at either serpent at close range since their bites do an insane amount of damage. With that said, look at the blue and red Mana crystals. These are what will be used to get close safely and hack at either serpents’ head. The blue ones works against the Blast Serpent and the red ones work against the Frost Serpents. Don’t worry about the aim since their hit detection is huge and hits are bound to connect as long as even a part of it connects.
You must destroy both at the same time or do it quickly as Medusa revives them after enough time has passed. Once both die, jump up to Medusa and hack away to destroy her barrier. You’ll need to use targeting here since most of the damage comes from hacking directly at Medusa herself(other targets are her base and two serpents). After enough time has passed or attacks are dealt, Medusa reverts to her normal self. This is the general method to beat her.
For the battle itself, the most important thing is to keep moving. Medusa has the same repetoire of gravity-based attacks as Thanatos Stroud, as well as a different version of his celestial gates. On HARD and ULTIMATE, Medusa also fires sonic waves on the ground which either petrifies or confuses Keldy. This attack has incredible range so try and keep your distance.
The Serpent attacks, apart from their many bites, include sucking up objects and spitting them out. One will do the sucking up of objects and the other spits them out. Keldy, if hit, can be burned or frozen so stay clear of the spit range. Their most dangerous attack is an extremely long lunge, which can kill Keldy rather easily. The telegraphing sign for this is when a serpent pulls itself back far and bends. They will regenerate after Medusa takes enough damage or time passes, but it’s no biggie.