Just a quarter of an hour after the club released the news of Brendan Rodgers' surprising departure via a perfunctory short statement, the howitzer landed, from the major shareholder, with whiskers twitching in obvious fury.
Through 551-words, major shareholder Desmond eviscerated his former ally.
The man he convinced to come to the club when their rivals were getting uppity in 2016 and needed putting in their place. And the man he again relied on after Ange Postecoglou departed to another club in the recent offseason.
Such was the severity of Desmond's takedown, the astonishing return of the former boss was practically an secondary note.
Twenty years after his departure from the club, and after much of his latter years was dedicated to an unending circuit of appearances and the performance of all his past successes at the team, O'Neill is back in the dugout.
Currently - and perhaps for a time. Based on comments he has expressed recently, he has been eager to secure a new position. He will view this role as the perfect opportunity, a gift from the club's legacy, a homecoming to the environment where he enjoyed such success and adulation.
Will he relinquish it readily? You wouldn't have thought so. The club could possibly reach out to contact their ex-manager, but the new appointment will serve as a balm for the time being.
The new manager's reappearance - however strange as it may be - can be set aside because the biggest 'wow!' development was the harsh way the shareholder wrote of Rodgers.
It was a forceful attempt at character assassination, a labeling of him as untrustful, a source of untruths, a disseminator of misinformation; disruptive, misleading and unacceptable. "A single person's desire for self-interest at the expense of others," wrote Desmond.
For somebody who prizes decorum and places great store in dealings being done with confidentiality, if not outright privacy, here was a further example of how unusual things have become at the club.
The major figure, the organization's dominant presence, operates in the margins. The absentee totem, the individual with the authority to take all the important calls he wants without having the responsibility of explaining them in any public forum.
He never participate in club annual meetings, sending his son, Ross, in his place. He rarely, if ever, does interviews about Celtic unless they're hagiographic in nature. And still, he's slow to communicate.
He has been known on an occasion or two to support the organization with confidential messages to media organisations, but no statement is made in the open.
This is precisely how he's wanted it to remain. And it's exactly what he went against when launching full thermonuclear on the manager on that day.
The directive from the team is that he resigned, but reviewing his invective, carefully, one must question why he allow it to get this far down the line?
If the manager is culpable of all of the accusations that the shareholder is alleging he's responsible for, then it's fair to ask why was the manager not removed?
Desmond has accused him of spinning things in open forums that were inconsistent with the facts.
He claims Rodgers' statements "have contributed to a hostile environment around the team and fuelled hostility towards individuals of the executive team and the board. Some of the criticism directed at them, and at their families, has been entirely unwarranted and improper."
Such an extraordinary charge, that is. Lawyers might be preparing as we speak.
To return to better times, they were close, Dermot and Brendan. Rodgers lauded Desmond at all opportunities, thanked him every chance. Brendan respected him and, truly, to nobody else.
It was the figure who took the criticism when his returned occurred, post-Postecoglou.
It was the most controversial hiring, the reappearance of the prodigal son for some supporters or, as other supporters would have put it, the return of the shameless one, who left them in the lurch for Leicester.
The shareholder had his support. Gradually, Rodgers employed the persuasion, delivered the wins and the trophies, and an uneasy peace with the supporters turned into a affectionate relationship again.
It was inevitable - consistently - going to be a moment when Rodgers' ambition clashed with the club's business model, though.
This occurred in his first incarnation and it happened again, with bells on, recently. Rodgers publicly commented about the sluggish way the team conducted their transfer business, the interminable waiting for prospects to be landed, then missed, as was frequently the case as far as he was concerned.
Repeatedly he stated about the necessity for what he termed "agility" in the transfer window. The fans concurred with him.
Despite the organization splurged record amounts of money in a twelve-month period on the expensive one signing, the costly Adam Idah and the £6m Auston Trusty - all of whom have performed well so far, with one already having departed - the manager pushed for more and more and, often, he did it in openly.
He planted a bomb about a lack of cohesion within the team and then walked away. When asked about his remarks at his next news conference he would usually downplay it and nearly reverse what he stated.
Lack of cohesion? No, no, all are united, he'd say. It appeared like Rodgers was playing a dangerous strategy.
A few months back there was a report in a newspaper that purportedly came from a insider associated with the organization. It claimed that Rodgers was harming the team with his public outbursts and that his true aim was managing his departure plan.
He didn't want to be there and he was arranging his exit, this was the implication of the story.
The fans were angered. They then viewed him as similar to a martyr who might be carried out on his shield because his directors wouldn't support his plans to bring triumph.
This disclosure was poisonous, naturally, and it was intended to hurt him, which it accomplished. He demanded for an inquiry and for the responsible individual to be dismissed. If there was a probe then we learned nothing further about it.
At that point it was plain Rodgers was losing the backing of the people in charge.
The frequent {gripes