Nemesor Zahndrekh
Nemesor Zandrekh (AKA "that old coot" or "Creedcron") is generally accepted to be the most bro-tier Necron overlord in the galaxy. He's a mix of Creed and Old Man Henderson, as well as batshit insane. Among a thousand other commanders who'd rather exterminatus an entire sector just to see their foes dead, old man Zandrekh makes a point of employing only honourable methods of war, giving his foes a chance to surrender, and capturing them alive if possible.
Zandrekh's prisoners can look forward to a pleasant stay at his flagship, having weekly dinners with their captor and witnessing the marvels of necron culture and technology. Until the old coot's bodyguard gets fed up with them and throws them out of an airlock catches them "trying to escape", that is. Speaking of said bodyguard, he's the only other necron who can stand Zandrekh's company, and has the doubtlessly cool-sounding title of Royal Vargard.
Why He's Such A Cool Guy
Well, Zandrekh did not take well to the biotransference process. In fact, it gave him Alzheimer's. As such, he tends to forget he's an immortal robot from outer space, and thinks he's still a necrontyr, from before the Eldar even existed. He's also nearsighted, making him see all of his enemies as Necrontyr as well, which in turn makes him quite a bit less xenocidal than most of his species. Woe the day he finds a pair of glasses, and discovers the green, smelly and burly necrons he keeps meeting around the galaxy are not what they seem.
Troll-tastic
Zandrekh lets you bring as many Deep Striking units as you want during your opponents movement phase when they bring something in from reserve. So use that flyer they have in Ongoing Reserves to trigger a Monolith assault on your opponent's ass and go in dry. You could basically pull off something akin to a Deathwing Assault using this asshole if you're using a fuckload of jump infantry. Heavy Destroyers and Wraiths come to mind. Maybe a Tomb Stalker if you have the gold for such a model. If you're playing Apocalypse and have Pylons in Deep Strike Reserve, throw that shit on the table as well. Just throw the most threatening shit you can at them and watch your opponent shit their pants in sheer terror as they have no fucking idea how to respond.