AU where Vader took Luke in but tragically died on the First Death Star before being able to proceed with his ambitions.
Fortunately, for the both of them, the young Skywalker has a few tricks up his sleeve...

Perching himself comfortably atop his high-backed chair, Admiral Wullf Yularen offered Lieutenant Commander Alexsandr Kallus an appraising glance. "Well then, old friend. What are your thoughts?"

His protégé paused for thought. "Griff, Montferrat, Sloane and I have committed to back you to the hilt. Sturn will naturally support you in order to weaken Galen's hand, although after tonight, his loyalty may start to waver. Eclipse, Obrax and Gradd will lean towards Marek of course, as will Lennox probably. General Veers will fall in behind whoever he thinks has the highest chance of keeping the fleet together; and so will Ozzel and his detachment back on Vjun, although that Caridan coward will likely defend it as a decision based on strategic necessity. We will need to scrutinise them carefully, sir."

The veteran Coruscanti commander nodded, lost in his own calculations for a moment before turning back to the younger man. "I agree wholeheartedly with your assessments. And now the items that you were too polite to mention?"

Kallus cleared his throat. "Frankly, sir? The majority of what happens next will depend on the contents of Lord Vader's Will. If you are indeed his successor to Death Squadron, as seems likely given both his lack of natural heirs and the lack of favour shown to Marek after his failures, you will gain by default all the officers who are reluctant to choose a side. That includes Piett and Solo, who by my own reckoning, seem to be very," he gave a devious smirk, "capable commanders to secure to our side."

Yularen swung round in reprimand. "Don't call Marek a failure, Alexsandr. We cannot afford to underestimate him. With the state of the Empire as it is, his past mistakes are now meaningless; the boy has intelligence, when he can be bothered to use it, and the rank and file will likely remember the favour Vader once showed him rather than what he lost. If Galen is chosen instead of me, we will have a bloody civil war on our hands; fighting amongst eachother for mere scraps as the Rebel Alliance lingers in the background. Frankly, Galen will be dangerous even if I am the one appointed as the heir."

Vader's Heir, Yularen mused to himself, as Kallus chattered on about which men he could count on once they were back on Imperial Center. Whoever helms the might of Death Squadron will have a hand on the throat of the Empire itself. No other would-be claimant could stand a chance…

Belatedly, he realised that Kallus had stopped talking and was peering at him as if waiting for a response. Reflexively, he gave a tone of vague assent.

"Yes, a very astute analysis my friend. Now, I want you to arrange a conference between myself and Deputy Director Ison as soon as possible. The entire command structure will have changed since the Emperor's death, and our contacts within the ISB may be our only hope at sorting through the rubble. I also want to know what the other fleets are up to now; this would be a perfect time for that pompous idiot Cassio Tagge to attempt a power grab. I absolutely refuse to abandon the Empire to those Hutt-spawned nerfherders!"

Without a word or order, Baron Solo followed Luke into his private officer. The Lieutenant Commander turned and raised an eyebrow towards the older man, almost half-mockingly, as if anticipating the nascent question upon his lips. The two Imperials studied each other for a moment, before finally Solo chose to broke the silence.

"You have Lord Vader's Will and signet ring, don't you." It was not truly a question.

Luke shook his head. "I don't have the ring. Personally, I suspect that he must have taken it with him to the Death Star. But the Will? Of course I have it with me. Frankly, after reading it, I should have disposed of it immediately. But I didn't. In fact, I saved it for you."

He leant over his desk, opened a compartment, and rummaged neatly through it. He pulled out a datapad, and passed it to Solo. "Here. Read it. So you'll know that I'm telling the truth instead of grasping at straws."

Solo took it gingerly. "This is..?"

Luke waved his hand impatiently. "Yes, it's his will, Han. Read it, quick!"

Solo stood there for a moment or two, his brows knitted in concentration. Finally, he nodded confidently to himself, then walked across the room to dispose of the datapad. He waited for a time, only turning around to return to Skywalker after hearing the clink-clank of the item as it made its journey through the garbage chute. "So, you are the Heir, then."

Locking gazes with him, Luke offered up a grim smile. "Yes, Han. He never told me that he changed his will, but I suspected it for a while. You can see now why I needed to conceal the Will. If the rest of Death Squadron had seen it here, while we're still in orbit, I would likely be assassinated within days. In order to strengthen my hand, I need his last commands to be announced on Imperial Center, in front of the army and as much of the general public."

The Baron bowed his head deeply before him. "Don't worry about it. By Talon and Treta, I swear I will keep you alive until then… Lord Vader."

Luke gazed up, sharply. "My name is Skywalker."

Han shook his head, staring almost with pity at the younger man. "Not anymore if you wish to survive what's to come… You're his son, Luke. No other claimant can rest easy should you still live."

There was a slow exhalation of breath, before Luke moved forwards to take Han's right arm by his wrist. "Then I promise to never, ever, forget, that the first man to help my campaign was Commander Han Solo."

I've not planned a sequel to this yet, but frankly writing about Imperial plotting is starting to get quite fun. I've had the chance to start reading Mary Renault's Funeral Games recently (its about the struggles between Alexander the Great's generals after his death), and I'll probably get a few ideas on how to continue this.

Most likely the chapter after this will be some sort of feel-good LukexMara fic. As a sucker for those types of stories, I'm starting to get the impression that there's not enough of them available. (for anyone who has not read it yet, I would really recommend Biology, Beloved by SpiderMansUnfriendlyNeighbor! Definitely one of my favourite L/M stories and just fanfics in general.)