Why is Zeriel so different from Asriel, if Zeriel is Asriel's reincarnation?
Zeriel is the perfect fusion of Asriel and Sans. So does have the best and worst of both. But is more than both, as Experiment Number Eighteen explains and shows, are more factors in the ecuation. And also, Zarethra also changing soul information and more the longer both coexist, as their soul despite being 1, is still 2 in 1, and is fusing more and more until becoming truly 1, and in the process, both affect each other, and this changes behaviour and more aspects progressively.
What is Zeriel's personality? And mentality?
Zeriel's personality is based on Asriel, with Sans parts and factors. Zeriel's mentality is Asriel's childish behaviour, along Sans' laziness. After losing his feelings, Flowey parts activate, and Zeriel's behaviour is way similar to Flowey when things are Genocide related, or suffering and/or pain related, and also changed laugh to be almost exact as Flowey's laugh with still laughing a little like Sans and childish.
Is Zarethra the villain?
No, she's not near a villain. She acts like that as has to do to make sure her plan succeeds. She does not hesitate in doing anything if is required or necessary.
What is exactly the relation between Zeriel and Zarethra?
They're married via prolongued time being together. They consider each other as lovers, one each other, and husband and wife in a differnt way.
How complex is UltSans as character?
UltSans is actually the most complex and twisted character, but also the most simple and strange one.
Are Zeriel and Zarethra legally married?
Zeriel and Zarethra are actually married, not in legal ways but yes in legal terms. Under the legal term or coexist together for such prolongued period of time, living together, makes them legally married, but their real marriage in relationship begins when UltSans after losing Papyrus, reaches to finally notice her, and so, in the same day they complete their marriage. At first, only Zarethra would say they are married, while Zeriel wouldn't be aware of that and try to understand while still developing; but after the required time, Zeriel would recognize the marriage, accepting it as actually real, but still not capable of being as good as wants to be.
As Fissure[1] and Error[2] have a favourite AU, does UltSans have a favorite AU?
Canonically speaking, he doesn't have a favorite AU.
For the moment, StoryFell is the temporary favorite, and FellShift Gold can also be used as favorite. But no Fanon version does actually have a favorite AU at the moment.
With further development, there will be a more clear view, and an AU or Timeline will be chosen as favorite. But for now as there isn't, StoryFell is the favorite, and not to visit or view, just because StoryFell Chara.
What does UltSans get by giving devices to AUs and Timelines for free?
He wants to get the code and all infofmation from each AU and Timeline. From the most basic that world has, to the most complex things or discoveries in technology or anything else.
What is the difference between Cross and UltSans if both grab things from AUs?
The execution procress. Cross gets and steals the ckde from other AUs to recreate his own. UltSans copies and obtains code and information as learning to have it himself too.
UltSans obtains as if his Personal Void learns and storages the code and information of any kind the AU has, but doesn't quit it from them. This means if an AU has a lot of technology, they will keep that, but UltSans will also have all of that technology too.
Is it recommended to agree or disagree with UltSans?
Can be rejected, but is recommended to accept if he offers a device. It brings a lot of benefits and perks and he doesn't steal so nobody loses anything. An AU gets games, security, a personal AI for each person, memory storage, and much more. Some AUs gets more benefits, as the Horror AUs that get food delivery periodically.
Why UltSans is never called by Sans?
UltSans hates that name, and will ignore it and think it refers to someone else. He remains using Raziel assfor him is how humans called him as happenned since always. His body and mind recognize Raziel, but his soul recognizes Asriel.
How would UltSans raise Aliza?
Uncounsciously, like a human. Is the only way he knows, so he would just raise her in his own way and style, but how humans would raise their children. The timeframes between foods, naps, playing, learning, and many more. He would take her to his original world to take the sun and play around like a normal child, and would also teach her himself the normal subjects from school but would be more focused on teaching her what is neccessary as magic and how his Personal Void works and other important relevant stuff.
From where is UltSans before isolated in his Personal Void?
European from Spain. This is important in the understanding of how atually weights to the reasons he had to do that genocide that would be later the 18th reset. Very weight.
Plus will also affect the way he raises Aliza too.
[1] Fissure's favorite AU is Underswap, all for the mayonnaise.
[2] Error's favorite AU is UnderNovela, never went there, but observes it.