WASHINGTON — When former Enron Corp. Chief Executive Jeffrey Skilling stands to face a judge and a possible decades-long prison sentence Monday, he will be — as usual — alone.

The death of company founder Kenneth Lay weeks after a jury convicted both men of fraud and conspiracy charges for misleading investors about Enron's financial health means that Skilling, 52, is the last person standing from the energy company's top ranks. It is a familiar position for a man painted by the government as both unusually self-reliant and occasionally self-destructive.

The single-mindedness that made Skilling a successful management consultant and a masterful corporate strategist powers his vow to go forward with an appeal. Skilling, who told jurors that he was "absolutely innocent," is attacking the four-year investigation against him as a "witch hunt" and claiming that prosecutors used unfair tactics and relied on shaky jury instructions to bring down a man who once dashed from presidential inaugurations to conference calls with Wall Street analysts.

"It's not in my nature not to fight something like this," Skilling testified at his trial. "I will fight those charges until the day I die."

But it is very much an open question whether U.S. District Judge Simeon Lake will let Skilling remain free pending an appeal, as defense lawyers recently requested, or whether they will order him into Bureau of Prisons custody immediately on Monday afternoon.

The judge closed the book on the criminal case against Lay on Tuesday by tossing out his conviction on 10 charges because he died before he could appeal. Thus, people who lost money in Enron's demise will watch what happens to Skilling with great interest.

Among the representatives for Enron's victims who have asked to speak at Skilling's sentencing is a lawyer for employees who lost what they say is more than $1.3 billion through the company's stock-heavy savings plan. The former employees "have all been condemned to many more years of labor to try and rebuild the hard-earned financial security that was stolen from them," the lawyers wrote in court papers last week. "Their lives have been shattered in ways that most Americans are fortunate to have never experienced."

Skilling, a graduate of Harvard Business School, transformed the Houston energy company from a stodgy pipeline business to a cutting-edge technology trader in the 1990s. But success — or, prosecutors would say, keeping up the appearance of success — wore on him. After ascending to the chief executive job in early 2001, Skilling was increasingly isolated from the opportunistic, hard-charging executives he called friends during his rise to power.

His best friend, former Enron dealmaker Clifford Baxter, committed suicide in early 2002 as the criminal investigation widened. His closest associates — including master salesman Kenneth Rice, youthful protege David Delainey and finance chief Andrew Fastow — all turned on him, pleading guilty and providing damning testimony that helped convince a jury to convict Skilling in May.