Opinion

More often than not, my favorite character would be the rival to the main protagonist, the antagonist who is not really evil, or the bad boy who ends up turning good when the real antagonist shows up. Those descriptions may not be exact, but you get the idea, Ureksa fits the general profile. However, as much as I appreciate him, my favorite Summon Night character is actually Sakuro. Sakuro is capable, while still having a sense of humor and a carefree aura after learning to overcome life's obstacles. I can relate to how Sakuro stays calm during the city's peril, until the situation reaches an unacceptable level, affecting a dear friend directly. That's how I am too, I'm calm and collected, perceived as too calm at times, but if I or a dear friend is affected directly, I don't take it sitting down. Sakuro is a Craftlord respected and skilled, but all he really wants is freedom and lets go of his title at the end of the game. I can identify with that too. I may not have a big important title, but that's just it, I don't want it. I'm not much of a career person, though I have the academic background to be, all I want is freedom.
I also like Rasho, one of the possible summon partners of Cleru or Pratty. He's direct and honest, sometimes to the point of being blunt, which makes me appreciate his sincerity. He can also be sarcastic and has his funny moments. He cares, but he doesn't sugar coat. I love technology, so the adorable robot summon, Zantek, is another favorite character of mine.

Back on topic, Ureksa is still among my favorites. Though I disagree with his extremes, his somewhat "loyalty over justice" methods draw me to him. Ureksa is willing to do anything for Rumari including sacrificing the world. The part I don't like, is how he's also sacrificing his friends (not to mention Rumari herself) along with the world and he doesn't really listen to what Rumari actually wants. I don't like it when people do stuff "for your own good" when you're clearly against it. Everyone should have the opportunity to choose what they consider to be best for themselves with their own perspective and priorities. That aside, in the Spiderman dilemma, I know who I would save first.
You don't know what the Spiderman dilemma is? Let me explain, Spiderman (and other super heroes, such as Superman for example) sometimes finds himself in a situation where he must save Mary Jane (or Lois or whoever) and save a bunch of people at the same time, which would be quite the challenge because of the situation they're in.

If you were a super hero, who would you save first? Your dear one, risking the lives of a group of innocents; or the greater number, risking the life of your dear one? I'll save whoever is most precious to me first. Priorities, that's the word. While I wouldn't sacrifice my friends to senselessly pursue revenge in the name of another friend, I would sacrifice the world for a friend, if I can spare my other friends. I play favorites, I can be fair if I want to, but can also decide to be unfair out of loyalty, in which case I can openly admit it, just as Ureksa can.
Either way, Ureksa is a good boy really, a bit confused at first, yet still a good boy. None the less, he was an antagonist who, for his own reasons that have already been discussed, ended up acting all bad boy. I'll admit I still have a thing for the antagonist that turns good. Such a character isn't good over something abstract like a "sense of justice" or "doing the right thing." This type of character has tasted both sides and made a choice after experimenting. We're not talking about a goody-goody here, but someone who is good by choice, not because of some unspoken sense of duty.

Maybe that doesn't fit Ureksa perfectly, but you get the general idea. He made a mistake and he learned from it. He's not perfect and that's what makes him endearing. The conflict of betrayal, the doubts of going through with his plans, the realization that he made a big mistake; it all makes for a good story and an interesting character. He's adorable and amusing. His temper tantrums are funny and it's cute how he looks so innocent while pretending to be a loyal Craftlord and so crazy when he's mad. Plus his guardian beast, Pouso, is just too cute. In conclusion, Ureksa is a vital plot device worthy of being examined.
Now for some wishful thinking, I know this is all very unlikely, but I can dream. I want Summon Night: Swordcraft Story to be remade for the PSP (currently my favorite system) with upgraded graphics and CG movies. The last tournament battle that was skipped after the Parista fight will be playable.

I also want it to be made into an anime where Cleru and Pratty are twins and they include all the four possible summon partners. Sugar can be Cleru's guardian beast and the previous summon partner of Shintetsu, who claims he promised her his son in marriage. Pratty can have Zantek. They can meet Kutty and Rasho as stray summons.
They run into Kutty and realize there's a summon causing trouble while they visit the volcano island on a picnic with Amariss. We'll have an episode of character introductions before the tournament is announced the next day. Cleru and Sugar become old enough to have summons and to celebrate, Amariss takes them out for a picnic on land (they live in an ocean tower remember?)

On the island, they find Kutty, who is being picked on by another stray summon and stubbornly fighting back. Worried about the fuzzy little green summon, they follow him. Rasho's element is fire, so he has the advantage near the volcano. Kutty's element is wind, Zantek has electricity and Sugar has water, the same as in the game. Cleru and Pratty go off to investigate and meet Rasho, whom they must defeat in battle.
After Rasho has been defeated in an epic battle with cool background music and shiny special effects, Amariss goes to find them because they've been gone exploring for too long. It turns out that Rasho was not really Kutty's enemy; Kutty was trying to help with Rasho's training.

Rasho decides to tag along for more training. Amariss, being the kind person she is, is happy that her son and daughter have apparently made new friends. Kutty tags along too. As a result they all end up in Wystern, where Rasho intends to train to become the greatest Oni king and Kutty just wants some more of Amariss' food.
Sugar will follow Cleru around everywhere in the classic anime situation of the super powered girl in love with a relatively normal boy. Pratty will have her amusing moments with Varil when Zantek says humorous things in his electronic R2-D2 style code that only she can understand and Varil wonders what's so funny. ("Are you laughing at me?!" "Haha, no, hahaha!") Cleru and Sugar will eventually get together. The same goes for Pratty and Varil. Overall, the main theme will be humor and action.

There will be fan service. I want Sakuro and Ureksa to go for a swim appropriately dressed for the activity. Ureksa will actually brush his hair back instead of letting it cover his face. He'll look like a man instead of a somewhat hard to identify creature. He will also have an alternate look when he's being openly controlled by Parista for the last battle, with a ridiculously tight PG-13 outfit lacking a shirt and involving black leather and multiple belts.
I'll watch the anime, take a billion screen shots and stare at them all day long. Especially the fan service Sakuro pics, and Rasho, and manly!Ureksa and Zantek. Yes, Zantek, I love robots!
The last tournament battle will be Cleru versus Pratty and it will be left as an open ending for the fans to debate about the winner for the rest of eternity (or so it would seem). Later, there will be a funny fan service special titled "Craftlord Party" where they reveal that it was a draw and both Cleru and Pratty share the title of Craftlord of Iron. Also, Rumari and Tyram will finally get married. The special will involve Ureksa running around helping with the preparations, warning his future brother-in-law that he better keep Rumari happy and dealing with a series of hilarious mishaps as they plan the party.