Okay, so I've been engineering this thought about a modified soul release for a while now. In comparison to other species, modified souls are left at disadvantage for no clear reason - for example, everyone understands that humans cannot quite stand at the level of others, but modified souls are supposed to be stronger than shinigami or hollows, aren't they. I mean, their name does scream 'enhanced', and if I recall right, the reasoning for their creation was the idea of creating super soldiers, right?

Except we all know how that turned out. All mod souls apparently are lousy fighters, minus the Red Pill edition, which are not even real mod souls.

Now, I am thinking of a release, that each modified soul is programmed with. A fight-or-flight zone, terminator form, killer mode - it could be whatever we want to call it, but for the sake of simplicity, I am calling it Modified Mode. Basically, it would be a form, that further enhances the combat capability of a modified soul; similarly to how hormones (ex: adrenaline) are released in a certain situation (let's say it's a fight), the modified soul (the container) would release reiatsu/substance within the host when provoked/threatened. This chemical release would temporarily 'morph' or 'modify' the host to compliment the powers programmed into the container - this would come with physical changes and visible modifications, not just an increase in power. While this is completely uncanon and original idea, I will try to explain it in a canon example.

You see, when Kon jumped into Ichigo's body, I doubt it was a perfect match for him. He brought his own powers of enhanced leg strength to Ichigo's body, showing off what modified souls accomplish within any host - ability to borrow the power within the container to the host. However, if we think it from another point of view, Ichigo's body wasn't specifically crafted to compliment to this particular ability, and thus, it might be possible, that Kon couldn't fully manifest his ability. That problem would be fixed with a Gigai designed to compliment his abilities, or... modify the host to bring out the ability's full potential. Do you see what I am trying to say?

The Modified Form would, regardless of whatever host they are inhabiting, modify it so, that it can act as a better vessel to the container's power. This could give a +1 AR like a shikai, but there could be a various levels of release - if the initial form is to 'modify' the host, another stage could be accessed by forcefully 'mutating' the host even more drastically to compliment the mod soul's power.

As no modified soul, except for the Red Pill edition, can have a zanpakuto capable of Shikai or Bankai right now, this would be a good thing as the species would get a release it deserves. Read: 'right now'. As you know, some modified souls will be allowed to develop a zanpakuto through in-character means, but they will have to train for it and they will have to abandon this release. More on this will come later, when Izuna and I finish our unending discussion on this subject - hopefully pretty soon, actually.

For most part, this is an idea fairly underdeveloped and a nice addition rather than a required installment. I am awaiting your feedback on this!

I think I see where this is going, perhaps if we do use this idea however a modified soul can develop other release forms depending on their host's race, ie if their host/gigai (or reigai) is of Quincy creation then they can use the Quincy: Vollstandig/Letzt Stil at the cost for this modified release. I think Modified Soul should be a very open race, after all they're so diverse and unique so I have a plan...

The Mod Souls I believe should get a the option of a "Host Body" this would be a gigai/reigai and this body would provide the benefit of being augmented by having a +1 AR, essentially this body doubles as  a "Shikai" kind of thing although is available to all Mod Souls, their next form (Your modified Form) allows them the further +1 AR to equal the equivalent of the "Bankai/Ressurreccion" although with Admin permission and since Mod Souls are meant to be super-soldiers then those who can apply for it at tier 2-1 can achieve this second form which gives them +2 AR (This would add with the bodies +1 so therefore the mod soul would have +3 AR like the Resurreccion: Segunda Etapa. It doesn't stack with the first stage). Although with the Mod Soul they can instead have a separate host body, thus making them able to use racial skills of other races by having a race specific body for example if Izuna was in a Quincy Host Body then he could use the racial skills such as Reishi Manipulation, Blut Hirenkyaku etc.

Now since they can inhabit different bodies with a variety of traits then I will suggest that they instead adopt that skill set essentially removing the benefit of the Modified Release, after all these beings are meant to be designed to be super-soldiers, they should have a few perks to them. They should be a very open race and as such they should be graded on how they turn out and not have all these limits placed upon them in my opinion. Note that just because Izuna is a mod soul I am not doing it to give me benefits or anything however it would be hard to simply take Mod Souls and restrict them since there are so many avenues you can take them down.

I partially disagree with your argument. The modified souls bring their own abilities into the host body, and do not utilize the abilities of the host (unless the host body was designed for them as with Izuna's reigai for example). A modified soul would have no way of access the abilities of other species. Here's why;

A) A modified soul could only possess an empty body (gigai or reigai), or a body, that will have it's spirit vacated upon taking the pill, such as Ichigo's body (substitute shinigami's human body). This would make them unable to possess living beings (quincy, bount, human, fullbringers, etc.), shinigami outside of gigai and hollows as they do not have an empty space within their body and cannot vacate it.

B) Even if they would be able to possess the above species, what makes you think they could access their racial abilities. While an echt quincy does naturally possess Blut and Reishi Manipulation, they must still train to control them on any level - not only does a modified soul lack this required training, but any knowledge necessary of drawing on these powers. They wouldn't know how to use Pesquisa or Cero as an arrancar either. All they have is what they have inside their pill. They cannot draw from the host.

C) The powers of modified souls simply do not work so, that they could possess an arrancar and suddenly access their Resurreccion. As previously said, they do not draw from the host for power in any way. All abilities and techniques come from the pill, and all the host does is to act as a physical vessel, so that these powers can be manifested (since they cannot do it in the pill form).

D) Personally, I think allowing a modified soul to jump to another body and simply taking it's power sounds fishy. They simply do not work that way.

hmm I like this idea of the Mod Souls having the ability to enhance their powers however I think we need classifications of Mod Souls with different styles for each like there could be ones who used this release through host bodies specifically made for this release and the Mod Souls Powers, another category which could use a racial body, hence they can have certain racial attributes and forms at the cost for their other forms such as Modified Mode or whatever it is. But this is my opinion.

I still disagree on Mod Souls possessing a quincy and getting Vollständig and all quincy attributes. This simply dictates against the powers of modified souls, which I stated before. If you want to play quincy, you could play a quincy. If you want to play a mod soul, play a mod soul.

I am concerned about the Zanpakuto of a modified soul, too. Practically any species could possess a zanpakuto, but upon doing so, the species is branded a shinigami hybrid, due to zanpakuto being essentially a shinigami-only thing (arrancars are half shinigami, mod souls not so much). They could still learn Shunpo, which is a regional variation of the universal High Speed Movement, and not really a racial technique. I am not sure about Kido - now, back to my point. Could a modified soul have a Zanpakuto? Maybe, potentially yes. Should they? No. Absolutely not.

Artificial shinigami is your choice, if you want a mod soul-ish character and zanpakuto. Modified Mode could be anything related to your character's type of MS, but it wouldn't be a Shikai/Bankai, a Vollständig or a Resurreccion.

Okay, so I am just going to say this should be implemented as a release for Mod Souls although those who are "Unique" can be mod souls with other racial attributes and forms although the term "Artificial" can be used with things like Shinigami, Quincy, Arrancar etc to those characters who were created with artificial abilities.