ENDER LILIES: Quietus of the Knights

The final boss of the game is located at the very bottom of the map near the center in the Abyss area. The blighted Heart respite is located just before her room.

In order to unlock Ending B, you CANNOT have the Luminant Aegis Curio equipped.
See:

The boss is a large figure with 4 spiked appendages coming out of its back. The weak spot is the jewel in the center of its chest. This tends to be just out of range of most of your attacks while on the ground. As a result Gerrod tends to be your best attack spirit to use as it has a large attack sweep and doesn't suffer a loss in power while in the air.

This boss has 3 phases, though the differences are fairly small. In between each phase, there will be a charging effect followed by a blast. It should be easy enough to avoid and is very similar to the phase changes you've seen from the previous bosses in the game.

Her actions and counter strategies:

- A downward stab with all 4 back appendages. The safe zones are right in the middle or at the very edges of the screen. As the bosses weakness is right in the middle... well, where you should be (and be pounding away on) during this attack should be obvious.

- A swiped along the ground from the middle outward with either the far left or far right appendage. When you see the boss reach one of those appendages to the very middle of the screen, move into the half of the screen opposite. You could also try to get high enough that the attack misses, but I find this unreliable and makes it more difficult to continue attacking.

- For her final move in phase 1, she can spit out these flying orb... fish... things. They are refered to as "Enhanced Spirits" in a guide that I've referenced in other solutions, though I don't think that is the official name for them. These are actually the most dangerous part of this fight, even all the way to the very end. They will take at least 3 hits from Gerrod to kill (usually getting stunned from the second). These orbs will occasionally fire blasts that slightly home in on you and deal roughly a third of your health bar in damage (more without protection relics and at lower levels). If left unchecked these things can quickly make it impossible for you to survive. You may want to focus on killing these over hitting the boss, particularly if you end up with more than 1 in the fight. Using Gerrod, it should frequently be possible to hit both these and the boss in the same attack, so switching focus shouldn't actually be as much of a disadvantage as it sounds.
During Phase 2 of the fight, the boss will occasionally spit 2 of these out in quick succession. Taking these out will take on elevated importance starting then.

- Starting in phase 2, the boss can stab either the far left or far right appendage straight into the ground, producing a shockwave that travels to the other end of the arena. If you see either of those appendages rise straight up, make sure you are not directly underneath it. I got caught under it once and was killed even though I was over half health at the time. The shockwave itself is fairly small and relatively slow, so jumping over it shouldn't be an issue.

- Starting in phase 3, she will lean, bring her hands together in a praying stance, then produce a blast of energy originating at the jewel. Personally, I never got hit by this so I have no clue how much damage is dealt; The move is highly telegraphed and easily avoided. The size is only moderate, basically just enough to take you out of range of attacking back, but I would travel to the edge of the arena to be safe anyway.

And that's it for this boss for Ending B. Realistically, this boss is likely quite a bit easier than a few of the previous bosses, but she is still fully lethal. Getting hit 3 times (without healing) can kill you, and those hits can come in a quick succession if you are careless or allow the flying orb population to get out of control.