Below are 3 more special characters to check out. Trazyn the Infinite is still one of my favorites besides Imotekh.
via Yakface
Illuminor Szeras:
It says that while the C'Tan provided the knowledge for the bio-transference of the Necrontyr race into Necrons, it was Szeras that actually made it a reality. He saw it as just one step towards the ultimate evolution into gods of pure energy (I guess what he saw the C'Tan as and wanted to be that).
So even today he continues his tireless studies into understanding all facets of life, presumably seeking the elusive secret that would allow him to become a 'god' in his eyes.
To do this, apparently he feels he needs to test on living beings, so he's constantly needing fresh subjects culled from invasions. Through his research he has come up with some the greatest advancements in technology for the Necrons, so his services are much sought after.
He is a Cryptek special character, so has a much more less powerful statline then the other special characters that are essentially super-Necron Orverlords. Despite being a 'Cryptek' in the fluff, he's still just a regular HQ choice (and you can't take a Royal Court for him because he isn't an Overlord).
For Wargear, he has an Eldrtich Lance and Gaze of Flame (Assault and Defensive Grenades for him and his unit).
His one unique special rule is that he upgrades a single Warrior or Immmortal unit with a random upgrade (you roll a D3 to see which ability gets picked...I mistakenly reported earlier that he upgraded D3 units, but that actually isn't the case. He only upgrades one unit)
The upgrades are: T5, BS5 or S5.
Definitely one of the more ho-hum named characters from a gameplay perspective, but he's also the cheapest by far, although the fact that you can't take a Royal Court for him does seem to make his uses even as a cheap HQ choice likely questionable.
Cannot take a Catacomb Command Barge or a Royal Court (as he isn't an Overlord).
Orikan the Diviner:
Orikan is the master 'astromancer' in the Necron race and is roughly equivalent to what Eldrad is to the Eldar (although I think Eldrad is superior to him in terms of future predictions).
Since Orikan knows so much about the future, he tends to treat other Necrons with scorn and disdain and this has made him less than popular and many would like to see him destroyed. Unfortunately, his skills are fare too useful for anyone to actually go through with that.
Unlike a Farseer, it seems as though his ability to predict the future is largely based on sheer calculations of even the smallest minutiae. However, unforeseen events, especially those based around the truly unpredictable nature of the warp can and do confound him. In order to maintain his reputation, he has access to some rare chronomantic abilities, which he uses to actually go backwards in time to change past events slightly to make sure his predictions actually come true.
Of course, every time he does this, naturally all sorts of other terrible unforeseen events also tend to occur based on what he changed in the past, but as long as his prediction came true, he cares little for any other destruction he causes.
Just as with Illuminor Szeras (the other 'Cryptek' named character) he has lesser stats than the Overlord style named characters. He does have a phase shifter though (3++ save).
His weapon is the 'staff of tomorrow' and its basically a staff that hits his opponents an instant before he actually swings it! That means he gets to re-roll 'to hit' and 'to wound' rolls, and it is a power weapon.
He has a special rule called 'Lord of Time' that allows him on one turn (and only one turn) to re-roll all unsuccessful reserve rolls that turn (unsuccessful rolls MUST be rerolled that turn, he doesn't get to choose).
He has another special rule that means all enemy units count as moving through difficult terrain on the first turn and if they are actually moving through difficult terrain then they have to choose the lowest die from the two they roll for difficult terrain. This obviously seems like a good ability to combine with the C'Tan manifestation that makes all difficult terrain count as dangerous!
The last ability he has is called 'The Stars are Right' and basically represents the fact that Orikan has predicted that at some time during the battle the stars will align and he will reclaim a portion of his ancient power (presumably from before when he was a Necontyr). He rolls a D6 at the start of each of his turns and if the die roll is less than or equal to the turn number then he has ascended to his 'empowered' state and gets a totally new statline that has S/T7, A/W4, etc...suspiciously similar to a C'Tan profile some would say.
Of course, you have to keep rolling at the start of each turn and if you ever roll less than or equal to the turn number again, his power recedes and he drops back down to his old statline (which could mean he instantly dies if he had already suffered more wounds than his 'lesser' profile has on it).
Points-wise, this guy is nowhere near as cheap as Illuminor Szeras, but compared to the rest of the named characters, he is still the cheapest.
Cannot take a Catacomb Command Barge or a Royal Court (as he isn't an Overlord).
Trazyn the Infinite:
He is a Necron who woke very early and is fascinated with studying and collecting history. His tomb world is filled with secret trinkets including (I quote) 'a giant of a man clad in baroque power armor' (start your wild theories here!). He even will attack other Necron tomb worlds to capture artifacts from them that he doesn't think they deserve.
He has a special weapon whose affect happens after a round of combat in which he has killed an enemy and after all blows have been struck on both sides. Given that this is not a power weapon (and he just has 3 Attacks), it is not a sure thing that he will kill anybody in combat!
But if he does, roll a D6 for every model (friend or enemy) that has the same name on their characteristic profile as one of the models that he killed that turn. On a 4+ those models take a wound (armor/inv saves can be taken as normal).
Example: If the he kills an Ork Boy in close combat, roll for all other Boyz in the same combat, and on a 4+ those models suffer a wound, but NOT the nob (as he has a different name on his profile). It would seem that if he was fighting against another Necron player, then this rule has the potential to hurt his own forces if the same type of units were facing off; if he was attached to a unit of warriors that was fighting against an enemy unit of warriors, for example.
He is also a scoring unit (because in reality when he's 'claiming' an objective he's really seeking to claim a hidden Necron artifact nearby, it says).
Also, anytime he is removed as a casualty, roll a D6. On a 1, he is removed as normal (but would still get a chance to use Reanimation Protocols as usual I presume as he has that special rule too), but on a 2+ you randomly choose another model from all the friendly Lychguards, Crypteks, Necron Lords and Overlords on the table (not counting named versions of those) and remove that model and replace it with Trazyn, who counts as returning to play with the same amount of wounds the model he replaces had. And it even specifies that he only gives out Kill Points when he doesn't return this way.
He also has Mindshackle Scarabs (which is a piece of wargear that other character-type models in the army have access to). These allow the bearer to randomly pick one enemy model in base contact before any attacks are made in CC that turn. That model must pass a Ld test on 3D6. If it fails the test, it instead does D3 attacks on its own unit using the weapons/special rules of the Necron player's choice (if the model has different weapons or kinds of attacks).
So while not a powerhouse or a character that boosts the ability of your army, he is a HQ that is a scoring unit which can give you a few different tactical options.
Can take a Catacomb Command Barge but CANNOT take a Royal Court.
Confirmed in WD 382, his cost is 175 points.