Hiruzen had every intention of swiftly resuming the position of active Hokage. It wasn't that he was obsessed with power, but rather that it was an absolute necessity for several reasons.
First, if Konoha were to hold a formal election right now, it would devolve into utter chaos. No one had prepared for such an event; not a soul expected the young Fourth Hokage, Namikaze Minato, to sacrifice himself so soon. Everyone assumed he would lead for at least another decade or two. Consequently, no candidate had been vetted, and no platform had been built.
Except, of course, for Shimura Danzo.
Danzo wasn't a fool; he had calculated this. He believed that by striking suddenly, being the only person prepared for an election, his probability of success would be massive. If he could force the nomination process, he could step from the shadows to the forefront and launch a massive propaganda campaign within the village. He truly had his procedures ready. Had things followed his script, Danzo might actually have pulled it off.
Unfortunately for him, his timing was abysmal. Instead of seizing power, he inadvertently provided the perfect opening for Hiruzen to step back in.
Secondly, and more importantly, Hiruzen resolved to return as Hokage to ensure the continuity and "purity" of the Hokage lineage.
People often wonder if Hiruzen ever considered Uchiha Kagami or others for the post. While such thoughts may have crossed his mind, when it comes to the actual exercise of power, the choices are far more restricted. As the head of the Hokage faction, he had to choose someone within that lineage. His consideration of Kagami in the past was solely because Kagami possessed the ultimate credential: he was a direct disciple of the Second Hokage.
What defines someone as being from the "Hokage lineage"? This is one of the unwritten rules of Konoha's leadership. It is defined by the concept of sensei-to-student succession.
The First and Second Hokage were brothers. In truth, during Hashirama's tenure, the village's administrative power was largely held by Tobirama. Hashirama was a god of combat, but as a village administrator, he was somewhat out of his depth. Thus, the transition from First to Second was seamless. The transition from Tobirama to Hiruzen was more turbulent, given Tobirama's death on the front lines, but Hiruzen was a capable hand who seized the reins quickly.
From Sarutobi Hiruzen onward, all the way to the Seventh Hokage, Uzumaki Naruto, the succession remained a single master-disciple line.
The Fourth Hokage was Namikaze Minato, Hiruzen's grand-disciple (his master was Jiraiya). The Fifth Hokage was Tsunade, a direct descendant of the Senju and Hiruzen's own student. The Sixth Hokage was Hatake Kakashi, Minato's student, yet another link in the chain. By the time of the Seventh Hokage, Uzumaki Naruto, the lineage was indisputable: he was the student of both Kakashi and Jiraiya, the hand-picked successor of Tsunade, and the biological son of the Fourth. He inherited the entirety of the lineage's political legacy.
Even the brief "Acting Hokage" Danzo was one of the original disciples of Tobirama. This illustrates that in Konoha, the status of the Senju and the master-disciple lineage is unshakable. Without a teacher from this lineage or the backing of the Senju name, the dream of becoming Hokage remains just that, a dream.
Take Obito, for example. When he shouted his loud slogans about becoming Hokage, it seemed like a pipe dream. But the moment he became a student of Minato, he gained the legitimate "qualification" for the office. Dan Kato likewise spoke of becoming Hokage; it seemed impossible until he became Tsunade's partner, which would have brought him into the fold. As for Senju Nawaki, he was the direct grandson of the First; had he lived, his path to the office was practically guaranteed.
This was the concept Hiruzen needed to uphold.
With Minato in charge, everything had been on track. But with Minato dead, the lineage faced a generational gap. Hiruzen's first hope would be for Jiraiya or Tsunade to return, but they were nowhere to be found. Orochimaru, who once would have been a candidate, was now out of the question.
Below Minato, his students had met tragic ends: Obito and Rin were "dead" to the village, leaving only Kakashi. While Kakashi was technically the sole successor of that line, he was far too young and lacked the experience for the role.
With no viable, stable successor to maintain the Hokage faction's grip on power, Hiruzen had to step up himself until he could groom a new candidate, much like he had groomed Minato. In his current plans, the candidate he had in mind for the future was indeed Kakashi.
In the original story, had Orochimaru not killed Hiruzen, and had Hiruzen served another few years, the Fifth Hokage might have been Kakashi rather than Tsunade. During that time, Hiruzen even prepared for the continuation of the line by specifically assigning Kakashi to be the teacher of Sasuke and Naruto, both of whom were considered potential successors.
For the Hokage lineage, this stable transition of power is vital. First, it ensures policy consistency. It prevents a scenario where a new leader immediately overturns the vision of their predecessor. If a Seventh Hokage develops a healthcare system only for the Eighth to abolish it, the village's resources would be wasted on internal friction. This is the necessity of centralized power. Second, it protects the interests of those who support the Hokage faction. If power isn't maintained, influence wanes, leading to instability and a cycle of infighting, exactly like the tension between the Uchiha and the Hokage lineage.
Thus, for both public stability and private interest, Hiruzen had to ensure this continuity. He had to retake the Hokage's power and begin cultivating the next generation.
With the support of Konoha's power center, Hiruzen was once again firmly seated as Hokage. Danzo, who had hoped for a "popular election," was left stunned and momentarily speechless, forced to endure in silence.
Once the leadership issue was settled, Hiruzen continued. "Very well. As planned, we shall proceed with the intelligence review. Regarding last night's events, who has information to report? On our end, we encountered the S-Rank criminal Rodriguez Diarmuid. However, it appears he was not the culprit. He showed a level of goodwill toward us; Kushina was saved primarily because of his intervention."
As Hiruzen finished, Might Guy and Kakashi spoke in unison. "We have intelligence regarding Diarmuid."
Hiruzen paused. "Report."
The people in this room were the absolute elite of Konoha; there was no concern about spies. Hiruzen allowed them to report publicly.
Guy glanced at Kakashi and signaled for him to speak. Kakashi nodded. "As Jonin, Guy and I were heading to support the combat units. We encountered Shinku-senpai and Hiashi-sama, who ordered us to maintain order within the village as the front lines were sufficiently manned."
Shinku and Hiashi both nodded, confirming the statement.
Kakashi continued. "After they left, we encountered Diarmuid, or rather, he appeared before us. We initially suspected him of being the mastermind and questioned him. According to him, he was not involved in the Nine-Tails incident but was tracking an individual named 'Uchiha Madara.' He stated clearly that the masked man controlling the Nine-Tails was this 'Uchiha Madara.'"
"According to Diarmuid's assessment, this 'Madara' is formidable, likely a judgment relative to Diarmuid's own strength, but possesses an extremely dangerous ideology. Coming from an S-Rank criminal like Diarmuid, someone he considers 'dangerous' cannot be underestimated. The release of the Nine-Tails proves his lethality. Finally, regarding this 'Madara's' abilities, even Diarmuid found him difficult to deal with due to a highly unique space-time ninjutsu. I cannot personally verify this. Lastly, Diarmuid claimed he was tracking 'a group' led by Madara. He informed us that when the masked man appeared, his companions were also around the village. I cannot judge the veracity of this, but I am reporting exactly what was said."
Many in the room looked shocked, but they let Kakashi finish before speaking.
"Uchiha Madara... surely it's that Uchiha Madara? If it really were him, he would certainly have the power to control the Nine-Tails with the Sharingan. But he should have died at the hands of Lord First long ago..." Hiashi said gravely.
Shikajin added, "We cannot conclude he is Uchiha Madara simply because he claims to be..."
Hiruzen shook his head, interrupting. "It is unlikely, but the Lord Fourth also mentioned the man claimed to be Madara. For now, we will use the codename 'Uchiha Madara' or 'Masked Man' for our records."
Hiruzen and Danzo were among the few who had witnessed the true power of the real Madara when they were young. They knew exactly how terrifying he was. Because of that, Hiruzen did not believe the masked man was the real deal. If it had been the true Madara, it wouldn't have been the masked man who retreated yesterday, it would have been Minato who fell. This wasn't a slight against Minato, but a testament to Madara's overwhelming power.
After a brief pause, Hiruzen continued. "As for whether the masked man had accomplices... he likely did. And that accomplice possesses incredible infiltration abilities."
"Yes," Kakashi added, remembering something. "Diarmuid mentioned his companion's stealth was so great that even he had difficulty locating them."
"Indeed," Hiruzen nodded, his expression darkening. "At the very moment the Nine-Tails appeared, the Scroll of Seals was stolen. Combining the timing, the coordination with the Nine-Tails' appearance, and the intelligence we have now, I judge that the masked man's accomplice stole the Scroll of Seals amidst the chaos."