This article describes the phase 1 of the final Momodora I boss fight for phases 2 and 3 see: Cheeoko

Lamia, also known as Underworld Queen Lamia, is the final boss of Momodora I.
She has horns, red eyes, wings and carries a green leaf. The green leaf could hint towards her having been a KoHo priestess some time before the events of this game who tried to oppose the gods.
The Fight[]
Before the fight starts she introduces herself and warns Dora about the consequences of trying to resurrect the dead. Her attack pattern consists of three attacks she repeats in the same order.
With the first attack, she throws a bunch of BAKs the same distance from each other around the altar in the middle of the room.
The second attack is summoning non-damaging smoke under Dora's current position. After a few seconds, a lot of BAKs rise from that smoke and then sink into the ceiling.
The third and final attack is throwing a large flashing ball at Dora. You have to use the Magic Leaf to volley the ball back at her, after which she does the same. You have to keep exchanging the ball until either of you fail to return it. To proceed to the next phase you need to hit her three times with it.
After the first phase ends, she summons Cheeoko, who you have to fight afterwards.
Strategy[]
For the first attack, I suggest to stand at either of the edges of the room since she doesn't throw the BAKs there. However, if you are standing in the middle when she starts it might be safer to activate the Shield. The second attack can be dodged by moving to the side when the smoke appears. The flashing ball shouldn't be dodged. You might think that spamming the attack button would do the trick and it does, as long as you keep a big enough distance from Lamia.
Overall, the first phase isn't hard and you shouldn't get hit if you know what you are doing.