Viceron the Dark Knight by Ixe
Not every Knight is a Valiant Jandarian. Viceron doesn't care about chivalry or synergies, he just wants to kill.
Balance
It's difficult to get a handle on Viceron with just theoryscaping. A seemingly obvious comparison is the SoV inductee Brimstone, but that comparison really isn't all that helpful. Their points are the same and their stats are similar, but Brimstone's slow-building special combined with Flying and bonding with Greenscales paints a very different picture than Viceron's solo, self-wounding act. Outside of Bloodstorm Ritual Special Attack Viceron's stats are impressive, especially when backed with Sanguine Sword, but he's not at the same power level as Cyprien, an equally-costed life drainer. Bloodstorm takes up a sizable chunk of the Dark Knight's points, obviously, an attack of which there is little precedent.
I'm just going to punt and leave this one up to the Playability section.
Theme
Utgar has dabbled in evil Knights before, though not magically-enhanced ones. Viceron is clearly not a nice guy, and potent to boot, so I can understand why Utgar would take interest. While I'm glad the Dark Knight isn't from Earth, I'm not entirely thrilled with Toril as the choice as the design does not harken to any D&D trope I've seen. But then D&D is very broad, in particular in the magic weapons department, so it's certainly within reason. Since we haven't seen any Humans from Feylund, Valhalla, Grut, or Icaria, I suppose Toril (or Eberron) is the next best option.
Merciless is a good personality, Knight works, and the stats are reasonable (5 Defense is high for a human, but not unprecedented). I do have a minor gripe with the name. I keep thinking of him as "Viceron the Blood Knight." There's nothing wrong with "Dark Knight," per se, but he just feels like a "Blood Knight" to me. Not enough of an issue to affect my voting regardless.
Creativity
The key creative piece here is the combination of a powerful self-wounding attack with a Life Drain-like ability. These powers both clash (they cannot be used together) and synergize (one hurts, one heals). While the obvious strategy would be to alternate normal and special attacks, the flow of battle isn't so predictable as to make that easy to do.
Playability
Viceron is suicidal. While it may seem that with some careful play he can, on his own, control a battlefield (or at least part of one), that doen't really work in practice. First, he doesn't like being near friendly figures, or rather, they don't like being near him, which puts him out by himself. For a Move 5 melee figure that's a lonely way to live; a death sentence, really, unless it's cleanup. While it may seem like Bloodstorm Ritual Special Attack is enough to scare away crowds, smart players will realize that swarming him is the best way to bring him down. Then the Dark Knight has to damage himself to deal with them. This normally plays out as a suicidal rush into enemy lines, some self-cutting, then death.
As noted it can play out differently in cleanup, but 150 points is a bit steep for the cleanup role. Additionally, a fair chunk of his price tag is tied up in Bloodstorm, which, given the cost of using it, is best restricted to efficient uses that hit clumped figures, not the scattered remnants in endgame.
While it may seem like repeated Bloodstorm Rituals could be devastating to an opponent, I quickly saw the folly of that thinking in my testplays. The problem (from Viceron's perspective) is his low Life. A Defense of 5 is solid, but even if Bloodstorm takes out everything around him there are almost certainly more figures in striking range, and if even one of them sneaks in a hit Viceron is on the verge of death. For a cheaper figure that wouldn't be as much of an issue, but 150pts is an investment that's hard to surrender, especially after only killing a squad or two of enemy figures. Of course he can then switch to his Sanguine Sword to heal up, but one attack&heal per turn usually isn't enough to overcome the counterattack. In practice, getting off more than two Bloodstorm Rituals in a game is a rare occurence.
That's not to say he can't kill his points worth, and more, but it's far from a guarantee. Those few turns Viceron is on the front lines are intense and full of tough decision points for both sides. He benefits a lot from having a delivery mechanism like Brunak as it cuts down the number of order markers needed to get him into the fray, though he needs to be able to distance himself from his mount before he starts Ritualizing. Heat of Battle is good for him for the same reasons.
Summary
I expected Viceron to be overly devastating, even at 150pts, due to the potency of Bloodstorm Ritual Special Attack combined with a reliable healing mechanism. But in practice he's just as likely to bleed out quickly without making a big dent. Either way, Viceron the Dark Knight provides for some intense, albeit brief, turns in the heart of a game.
I vote

to induct
Viceron the Dark Knight into the SoV.