[@TheWindel]
First I love the organization of the sheet, its all nice and colorful. Certainly shows quality.

Let me start by saying this is going to be hard to critique since you have this character paired with another that hasn't been posted yet. I'll do my best to critique what I can here but information left in the paired character might change my mind whatever I say here.

My first issue with this sheet as you are [i]really[/i] vague with her overall character. If you want to keep some information out of public eye, that's fine, and I certainly don't mind the mystery behind what she is and all because thats actually pretty interesting.

However there are areas with her abilities and lack of weaknesses to compensate for her versatility that makes this hard for me to critique balance wise.

To start; "♔ Synthese: Whatever the Empress is, it’s shape and form is enough to influence the world around her wherever she goes. This phenomenon takes the form of an invisible mist of disease and pestilence with a wide variety of results on the intended victims. How far the Empress can extend this sphere of control is something she has yet to disclose, but one can assume she can poison entire cities quite easily. As this can be quite bothersome to approach allies with, she can determine when to activate the Synthese."

While this ability is interesting, the biggest issue I have with this is what it [i]does[/i]. While you do describe it acts as an agent of disease and pestilence you also say it has a wide variety of results on the intended victim. In addition for it to having an incredible range, this is concerning because as a gm I'm not sure how powerful it is; nor on who would be effective or uneffected by it. SINCE it is based on disease, I recommend that it only applies to living, organic characters (This excludes undead, and various supernatural entities) and that perhaps you can list what exactly this disease can do to its victims. 

The alchemy and Colgarity abilities are fine. However I'd like more description on her summon; both its physical description and size, and what its exact powers are. Depending upon how powerful it is may require drawbacks such as damage sacrifice, limited time for summon, etc.

As far as weaknesses go, while the first is interesting since she can't be far without her owner; I'd like to see an additional drawback to her form. She seems to be based in some sort of alchemy, at least in her physical body anyway. Some weaknesses could include, for instance, that direct contact with water could make her fall apart or if she's stitched together like some kind of frankenstein monster she needs to be careful over physical exertion as to not tear herself apart. Since you were vague with what she is, its hard for me give any weaknesses aside from guessing what she is and offering suggestions. If the former ideas wouldn't work, I implore you to add some more physical limitations of your own.

With all that said, the sheet otherwise looks in order. I will refrain from giving a full judgement until KoL posts his character for me to review as well, however.