You fight her in a cut scene only that is choreographed/so you don’t actually have to play the fight, and he asks “are you afraid to strike the face of this body?” and knocks you into a pillar (the only one left…if it breaks in the fight the cut scene brings it back) and goes to stab you. The game sets this up as if he will actually succeed too! It has your character, no-matter how strong it is to have genuinely ‘lost’ the fight here and unable to get away from him/the pillar.  He then fails to control the body. Melphonsina now is in control…a little, and calls to you and Gettemhart saying she doesn’t want this to happen, if you kill her you’ll kill the Emperor. Then he comes back and says “alas that’s the end of her”.
So, his ‘the other soul/mind is ‘devoured’ thing wasn’t entirely true or he just knows how to push the other person down & here he didn’t do it enough so she blocked him that once.
She goes to stab you again, but now Gettemhart blocks it…very badly. He takes a full frontal double stab from both of the giant daggers. They’re enough to go all the way through his upper chest. They are non-photonic and that was both lungs. He should be unable to talk at all.
He asks anyway, “how can he die and not fulfill her wish, he’s still got his pride.” But pulling them out  and throwing them down, he knows he’s not enough to defeat the Emperor, his soul, the damned strength it’s better than nothing, he doesn’t want to die doing nothing, then he can’t face Sina. So he strikes at you instead, with his red energy.

This creates a…parallel dimension maybe? It’s gray fog for the floor, and wavy gray water stuff all around in a dome over the two characters. You stand back to back with original ARKS Gettemhart. He says he’s been consumed by Elder and now he will be consumed by a Guardian? Hah, what a weird twist of fate it is. He knew we had the same aura when we first met on Naberius but he never imagined being absorbed by you. He won’t eeeeven bother asking what’s going on, it’s all a whim of the Akashic Record after all, just thinking about it is useless, so he’ll roll his eyes and shrug about it. Now, go use his power, the power of Elder that he has acquired.
So, Arks-Gettem did really live on after he ‘vanishes in dust’ after the planet destroying ‘mountain elder/arms’ boss fight. Remember: the ‘elder-falz’ aspect or whatever that was knew Arks-Gettem was a hot-head crazy man who was super easy to lure with promises of big fights and unlimited power. It had him murder a girl to open a seal, and then took his body, killing him. You would occasionally get a flash where it’s really him in there, because it was forever-dueling personalities in there. This proves he’s…still mentally intact (if not bodily so) and has learned there is such a thing as Akashic Record. But just how much does he know? He’ll tell you to ‘show him’ something so is he like a ghost stuck in the gray area, but able to watch things randomly in Omega?

Now, he turns to face your back (as your char never turns around) and he changes from his guardians coat to his persona/elder looking one, but instead of pink highlights (on the knuckles-diamonds & chest area) and pink hair tips, it’s now lavender and somewhat purpleish for these areas.

Game Mode Explanation:
What this does, is give you the “Falz FORM” special attack mode.
This is where you can turn your char into an Elder clone and use several of its attacks. You level this up by defeating enemies and spending points in the various categories of defense, attack power, and special attacks. You can choose the look of the form as either a ghostly ‘overlay’ type that hovers over the character while the real character is still visible or, the actual character summons the form over-top of itself to become it. They both have the same ability set/it is just cosmetic. The mode works via a fill-gage and can be used once per mission only. The form is customizable too, you can later control the color of its glows and the ‘skin’ area. (So yes, pink and green candy colored Elders can and will be running around in regular game-mode)

You turn to face him. He requests you to save them, show me how you handle things. The odd…area of gray scene ends and Xiera says “you got his photons” and you can turn into Elder right now so it does it. The game will just do this, it’s a scene.  Xiera is confused it’s like you’re a darker. Schlegger laughs at a power that is similar to his, so you are sure to be a worthy opponent.

The elder form you get can be customized in the game to have various colors later. But, when it first appears it is black with dull bronze trim and blue photonic glows and purple accents. It crackles with the red lightening type energy that Schlegger has as well. He then turns into Elder Form as well, but his has the original trim of black, with gold. Its back fins are spread and the head/helmet whatever that’s supposed to be is Omega-format so it is fancier. He says it will be a 1 on 1 now.

I’m Not Alone
There’s Three Here

If you say I’m Not Alone they entrust our thoughts to you, use everything to hit him now. You battle him in a cut scene, throwing him through a column before reverting back. He says its overwhelming strength from the guardian. There’s also that failure there, where he sees Gettemhart standing there in a flash. He thinks it’s incredible he lost, and he then vanishes the falz form and leaves the Melphonsina body on the floor again.

Xiera rushes over and asks if you are all right.

This Power…
Besides That, The Other Two…

If you try to prompt her with Besides That, The Other Two…She says Gettemhart is gone and Mel is…But a voice comes out of nowhere and shouts at you “oi, you! Show me your thanks for letting you use my strength in this.” You nod, and the ghost of Gettemhart appears over the character as a sort of static filled overlap/overlay. Once it solidifies, your character has vanished/it’s only him now.  It walks up to her and confesses “that was a bad performance we had.” She can open her eyes and turn just a little to him as she lays on her back. She says “Well, taking a hit instead of being used as a doll, that was clumsy of me.” Gettemhart assures her we finished it. She says “yea she saw and it was expected so thank you. It took forever getting here.”  He tells her “yes it did” and pats on her. She’s so tired, but everyone won’t get mad if she goes to sleep now right? He says he won’t let anyone who took a break say anything. She cries, and closes her eyes. She tells him goodbye. He says see you, Sina. She glows red and turns to dust that dissolves upward into the air. He looks up, and the ghost of Gettemhart vanishes. Schlegger was wrong about eliminating the mind/soul of whoever he posesses. Why defeating the Elder/Falz form somehow defeated Schlegger is unknown. If he really possessed her body, that would not have eliminated him. It could have weakened him enough that she just comes through/stays there until she died.

Now, you’re in the gray area again. Gettemhart claims this is our final stop, for both Sina who is a memory and for him, who no longer exists. This is the end of their record. It ends and you look up at nothing. The gray area is gone, you were always just standing in the throne room, doing nothing. However, this isn’t the end for you, there’s things you still have yet to do. Xiera rushes over again, saying Ephemira is still the root of it, there’s still evil and there’s still so many castles. We have to do something to fix it, to fix all of it…or how could we face those two. You nod at this and look around the empty throne room.

The mission ends.
This was based on target damage.

A surprisingly very sad and very creepy chapter.
Creepy because being able to turn into Gettemelder is just ‘very not right’ on basic principles of well…anything actually ‘good-guy’, and also his ghost being able to I GUESS possess you because of this is also not fabulous. He SAYS (and actually does really believe) that he’s at the end of the record but he really isn’t. As this write up is 1 entire spoiler, he will turn up again. 
The more you think about Schlegger’s proposal the creepier he gets.

Questions raised:
Was the old man Schlegger not his real/original body because he is a bodysnatcher?
Why is Elmir so much younger than Schlegger (if he’s bodysnatching that’s the answer)
How does giving you Elder Falz energy to transform actually work?
Is there a Melrondia around somewhere?

Never to be answered:
If Schlegger hadn’t murdered them, how much longer would they live?
It was fairly clear Gettemhart & Melphonsina did probably not have that long to live anyway. He was coughing blood on the way there and she was always tired. Did they have a year left? Maybe, but they seemed to know that the modification/manna soldier thing was killing them rather swiftly.
Cut Scene good: The Elder/Gettem form takes getting used to, to actually use in boss battles or against enemies. It doesn’t even start out strong (when compared to a high level character) It’s a very smart move they didn’t make anyone have to actually use it in a fight here and that it was a cut scene instead. A wise move.