Or, canon update time! So many spoilers for the end of Kiva in here.
Meanwhile, in canon:
Taiga was originally taken from mid ep 40 because that was the point where he was most confident that things would go his way and less likely to completely snap and kill things. Canon proved us right... at least about the snapping. Here's a quick rundown of important events.
* Wataru rebels, and hard. Taiga wants Wataru by his side; Wataru wants to side with humans. They fight, a lot, and it tears Taiga up inside. But he can't not fight Wataru because he's King and needs to protect his people. However, right up until 47 Taiga maintains hope (if a little inconsistently) that if he can just beat Wataru he'll see the light and join him.
* Mio puts plans in motion to kill him. At first she wants Wataru to do it but when Wataru refuses she decides to agree to marry Taiga in order to betray and assassinate him. This culminates in Mio stabbing Taiga in the gut moments after saying their vows.
* Taiga tries to turn Shima Fangire, and ultimately fails. Shima demands death rather than be Fangire and Taiga appears to comply (sparking Wataru's first real earnest attack on Taiga) but secretly healed him and turned him human again.
* Mio dies. After the stabbing Taiga gets into a fight with Wataru (over Shima) and is about to be killed. Mio steps in and takes Wataru's attack, and appears to die from it. Until Taiga finds out the real killer he believes Wataru did it and this is the only time he maintains any real anger against Wataru for more than a few moments at a time.
* Bishop betrays Taiga. We find out later that Bishop was the one who really killed Mio. Taiga is justifiably furious but Bishop doesn't think he should be and after being attacked decides to remove Taiga from the position of King and resurrect 86 King in Taiga's place.
* Episode 46-47: Or, it sucks to be Taiga day. Firstly Taiga is actually willing to make amends with Wataru but this seems to be rejected and they end up fighting. Taiga loses, badly, and Wataru says they can't be together. Taiga is very hurt emotionally. Then Taiga's company fires him...because he lost to Wataru. Then Bishop shows up and tries to kill Taiga, nearly succeeding until Wataru shows up and declares himself King (effectively announcing to Taiga's mind that he is trying to kill him too, because the way to become King seems to be to kill the previous one orz). So Taiga goes to Maya, completely broken and vulnerable, asking her to give him Dark Kiva (read: give him the ability to defend himself from the people who are trying to kill him he thinks) and she refuses. Considering his mindset this is like the absolute betrayal/show of favoritism to Wataru in that she's leaving him to be killed (he thinks). Taiga even accuses her of "loving Wataru more" before he appears to stab her. Then Kivat II shows up and Taiga gets Dark Kiva.
* Episode 48: Taiga shows up to fight Wataru, who initially refuses until Taiga claims (he's...lying) to have killed Maya. They fight. Bishop shows up with an army of zombie-Fangire and they fight together to defeat them before resuming their fight. (Bishop is then killed by Nago and sends his life energy to the revived King) But then! Wataru stops the fight in order to hug Taiga and say he understands Taiga's loneliness and will be by Taiga's side. Taiga is just completely blown by this seemingly abrupt change from wanting him dead (he thinks) to wanting to be with him. Then Shima shows up and it is explained to him that Wataru was doing what he did to defend him. Taiga is unsure. But before anything can happen revived King shows up and starts kicking their asses. Wataru appears to be thrown off a cliff and Taiga is kicked around alone (no doubt believing his beloved brother dead) but then! Wataru returns. They join forces and kick revived King's ass. Afterward Taiga is reluctant, guilty, and doubting his ability to be King. He talks about sins that can't be forgiven. But then Wataru forgives him anyway "Your sin is my sin" and then Maya (who he just knocked out) shows up and forgives him too. Then Taiga acknowledges Wataru's strength and wants to prove to himself his own worth ("I want to surpass you") as both a person and King. Maya suggests they fight to truly know each other and "become one" and they do.
* Epilogue: Can mostly be summed up by "Wtf Masao and Neo-Fangire" but there are a couple important things. One, Taiga is again head of Development and Pioneer and moving ahead full-steam on finding alternatives to life-energy. Two, although his board is extremely nervous and clearly expecting to be offed... he doesn't seem to have any interest in any revenge or punishment. Three, he's a lot more confident and business-like. Dressing and acting the part of an actual president rather than being in jeans and all "you take care of it guys"
Time and place:
I'm taking Taiga from right post their fight, mostly because we don't know enough about Masao and the Neo-Fangire to be able to play that out effectively. However for the sake of having him as fully matured and confident as he gets post-canon I'm letting him be aware of two things via Camp's time-space bending. Without these things Taiga would probably be very worried/fretty and too anxious to get home (he'll already be a little anxious because he wants to get started) and not knowing would negatively impact the self-confidence he's supposed to gain.
One: he knows Bishop is dead.
Two: He knows he's been reinstated as president of Development and Pioneer.
How he figured out the first I'm I could go a couple ways with. It's possible he sensed Bishop's death/the taint of Bishop's energy in revived King. Or he could find out the same way he will/has about his reinstatement. Via a letter of apology from his board. It's likely that one of the reasons the board fired him was Bishop in the first place, considering that if a Checkmate Four had turned on King, who also just lost to Fangire's enemy, it might be a good idea to jump ship so to speak (rather like rats) and then discovering he'd defeated Bishop and revived King and was still King himself (and not only capable of, but likely having the right to severely punish them for things) they would be very very eager to get back in Taiga's good graces.
Changes/effects: (ie the meat of the essay)
The biggest changes are that Taiga has been jesus'd by Wataru and went through a harrowing experience that has allowed him to grow and mature as a person. These will effect him in several areas.
General:
More mature and focused. More self-confidence but also more open. Looking at the big picture(s) more than his selfish wants and desires (though this will develop more over time). Less desperately needy for affection/love. He'll also be less prickly about slights/insults and more willing to forgive people for things even if he isn't particularly fond.
Humans:
Taiga spends most of canon really disliking/disrespecting/distrusting humans. He calls them cattle. He fully expects them turn on Wataru when they discover he's part Fangire. Even though Taiga didn't approve of gluttony or killing humans for fun/sport it wasn't for humanity's sake. It was because both of those things ran risks of letting humans know about Fangire and if they know about Fangire they can become a threat to Fangire. There's signs of his opinions starting to change even before the end though, in the case of returning Shima's humanity.
After his jesusing, however, he wants to forge a new future of humans and Fangire together. He's actively seeking an alternative to feeding on humans. It's very likely he's either altering or completely removing the law forbidding humans and Fangire to love/marry (I am not sure he'd think more hybrids like Wataru are a good idea, but I also don't think he'd want to punish people for such things. Still, he'd be an advocate of contraceptives in cross-species relationships) and he's definitely changing Development and Pioneer's true focus to be the same as its public face, ie actually pursuing and funding advancements in sciences and technology all the time rather than just enough to make it appear so.
This doesn't mean he'll suddenly be all lovelove towards humans though. He had his trust of humans broken badly at a young age and that won't be repaired overnight. He's realized that there are many good humans out there and will be happy and mostly comfortable being friends with them but he'll be still a little wary of humans in general and it will be very easy for a human to turn him off of liking them for a long time. And while he's actively working on reducing his speciesism he won't be able to completely kick that overnight either.
On the other hand, now that he's wanting to work with humans he'll be more open about what he is and what he wants, at least once he gets to know the person(s) in question.
Powers:
His powers won't actually change in Camp (though it's implied that after his last fight with Wataru he's gotten somewhat stronger in general) unless we get a Kivat II (APP DADDY-BAT) and he can use Dark Kiva.
However, his self-confidence is a lot higher so he'll actually be more decisive in using them when he does use them. On the other hand, he'll completely change how he uses them. Now that he's decided to work with humanity he has no reason to attack and/or test humans in Camp, so no more potential boss battles (unless Camp 'helps' his summoned monsters get out of his control) but instead he'll be a lot more willing to jump into fights and help out people in need, like the other Riders. Since he has no more worries about revealing Saga's presence in Camp creating him enemies it will also make him more willing, though he'll still be generally careful about revealing his identity.
Lastly, becoming a good guy does not mean he won't use deadly force to protect his friends and family if they are threatened, though he'll be far more likely to start small and work his way up than being all "KILL IT NOW >E"
Love and relationships:
Throughout canon Taiga has two extremes of relationships. One is a purely business-type relationship, usually boss-subordinate and/or king-subject. This is how he treats most Fangire, especially Kurosawa and Bishop. But he relies almost solely on the authority of the title and not so much on his own natural leadership qualities. In Camp this is Xanatos, Yzak and Daisuke, among others.
The other type of relationship is one where Taiga is seeking love and affection, and lashing out in a hurt way where it isn't given. Taiga is extremely starved for love and affection and will jump on it when it appears to be given, or he thinks it should be given (his reactions to Mio and Wataru are prime examples). Even when he's trying to withdraw behind a mask and is lashing out there is an undercurrent of "Why don't you love me?" to it. There is me rambling about Taiga, love and affection and how he deals with this type of relationship essay-type-thing
here. It was supposed to be a sexuality essay but got sidetracked into a "how Taiga expresses love" essay It's mostly correct, though I need to expand and clarify on Mio and Tsurugi at some point. The most salient points are that Taiga at best barely differentiates between the degree of love and by type pretty much not at all. And that he also goes all out and/or responds badly when it's denied.
In Camp Taiga ended up with more of the latter because he was selfishly needy and continued to seek out the people he got affection from and more or less ignored the ones he didn't. This is a natural thing because being affection starved and suddenly given affection would encourage him to pursue it.
The biggest change with this will be his newfound self-assurance and confidence. And also his knowledge that he does have people who will love him no matter what. The changes will be small, especially at first. Now that Taiga is more assured he won't be spending so much time actively seeking and reassuring himself about affection. He'll relax (to varying degrees, which I'll talk about in a minute) in his current relationships and start pursuing new relationships in more ways than just affection. He won't stop seeking out new relationships where there is affection but it won't be his utter focus. He'll start pursuing business and casual-acquaintance type relationships too. He'll be slightly more reserved with new people in most cases.
The second change is that he'll start, not consciously, structuring his relationships in terms of degree. Right now he has a nebulous cloud of "gives me affection" at the top and way below it "business/tool" and then below that Xingba (who is the only person he really actively dislikes in a predictable manner). Once he starts (re)structuring things will develop into tiers. His family and most precious people will be towards the top with other tiers for good friends, slightly more distant friends, respected persons, casual acquaintances, business and so on down to... Xingba. It will be fluid, especially at first, but the end result will probably look something like this:
family
Wataru, Maya
Tsurugi, Mio, Otoya, Nana
friends
Sera, Rue
Serifar, Cooro
Husky, Cielo
respected and liked
Ash (Trine)
... and so on.
With his new confidence he'll relax in how he treats people. Fewer presents and grand displays of affection (though he will still give them out, especially to "family") and he'll generally be content to let the other person set the tone of things rather than pushing for more like he occasionally has been in Camp so far. He'll also get less possessive and be more open to...well, sharing their affection with other people. His protectiveness will stay pretty high but he won't stalk so much; he'll trust that they don't need his presence every moment of the day. Family is the most important so he'll pay them the most attention. Though he won't neglect anyone that is respected or higher.
Eventually, and this is likely years down the road, Taiga will have the experience and the settled relationships to figure out, say, the differences between family love, romantic love and friendship instead of relying on a "Well, they aren't family but I love them so they must be friends." sort of method. This is... not likely to end up happening in Camp (On the other hand I wasn't expecting him to end up in a romantic relationship nearly so quickly either. Which I will essay on next) but I'm mentioning it anyway just in case.
Corollary- Physical affection:
In canon Taiga is the chaser in relationships. It works out that he is pursuing people for love and affection rather than receiving it at first. His response both when people pull back from him (his conversation with Wataru in 39) and when they start showing him affection (other times with Wataru, and when Mio is talking about their wedding) is to show some sign of physical affection, usually a hug but also arms around the shoulders and hand clasping. In canon these never last very long but with the exception of the last hug from Wataru he is always the initiator. Taiga likes all affection and likely got hardly any at all (if that) as a child. His lack of experience makes him very awkward about it, but also gives it more impact.
But then Taiga met some very physically affectionate people in Camp who started giving him hugs and touches without him doing something first. He started liking and eventually reciprocating and quickly got into the habit of seeking out those people who he knew would give him hugs and such when he was upset/worried. He also started to be just a bit more free with initiating contact when in a good mood or particularly upset one. There was a slight confusion/substitution of physical gestures of affection for other signs of affection, especially with the people who frequently initiated contact with him (hugs=love sort of thing) and he was generally confused about it. But it was nice and he wasn't going to say no or otherwise refuse it.
But there was a bit of an awareness that it's not really something just friends do, and even family doesn't do it often (though, Maya is helping to... correct this). He still has these ideas so now that he has more self-confidence and less neediness he'll pull back on the amount and degree of physical affection with most people, at least for a while. He still won't refuse it when it is given, but he'll stop actively seeking out situations where he would receive it and in many cases substitute for something milder, at least in public.
How long he maintains these ideas and what his ideas change to, if at all, really depends on what he ends up perceiving as normal. He doesn't seem to have had any personal experience with physical contact in relationships and only limited socialization outside of specific social situations (schools, business etc), considering how good he is at business and how much he fails at personal relationships, that he only has vague ideas rather than concrete ones. And vague ideas can be changed based on experience. Whether his will or not, who knows?
Mental flexibility:
In canon Taiga can be very rigid in his thoughts. A "this is the way it has to be" sort of thing. Black or white, human or Fangire, love or hate. But by the end of canon Wataru (and I wouldn't be surprised if Shima had helped offscreen) has shown him the grays, the blurry lines and opened him to the idea of new things.
This is a really new concept for Taiga and he's trying to adapt. It will take a while but he will start seeking out new ideas and experiences to broaden his horizons. He's going to be very conscious of this at first, actively comparing what he knows to new things and probably disregarding the new things at least half of the time at first but he will get better.
... I think that's everything I needed to cover in this essay. I think. If I've missed something (or something else would work better in another essay) please tell me.
Now I need to essay on Tsurugi. orz.