Honestly, if I had to rank them, I'd go: Minato, Hiruzen, Hashirama, Tobirama, Tsunade
Minato and Hiruzen get their rankings with me because they were never defeated in battle, but willingly made the conscious decision to end their lives due to unusual circumstances.
Hiruzen wanted to ensure Hashirama and Tobirama weren't used against Konoha and prevent that from ever happening again. Despite later being mortally wounded, it was noted that he wasn't even bothering to dodge because he was going to die anyways. And while the Senju brothers weren't at full power, his diminished strength from his old age was noted repeatedly throughout the fight. Ultimately, I put him below Minato due to his inability to seal away Orochimaru after getting stabbed with a sword and two of his students both noting Minato was better.
Defeating Kurama and Tobi almost effortlessly while protecting one's village, dying wife, and infant son is utterly absurd, but he pulled that shit off. And whereas Hiruzen couldn't muster enough strength to drag Orochimaru's entire soul while impaled with a sword, Minato somehow manages to drag Kurama's chakra into Naruto with impaled by a giant nail. He even expanded FTG's power into creating a T/S barrier that permits him to transport something as big and powerful as an entire Tailed Beast Bomb to another location of his choosing. Potentially, he could transport opponents into outer space or the depths of the ocean and that's just not fair at all.
Originally Posted by Numinous
Considering Minato is yet again analyzing the ground AND Kakashi confirmed is assertion, either Kakashi is a sensor even before getting the Sharingan (we know he's not) or they're both NOT sensors.
Those are thoughts bubbles (which are identical to those at the top of the page), not speech. It does come off pretty strange since the thought bubbles are around Minato's arm so I understand your confusion. It's why I wondered if it was a bad translation.
The bottom three panels are all a continuation of one person's thoughts, the Rock ninja who's freaking out because it looks like "The Yellow Flash", but because Minato seemed to be alone from that angle, he thought he was fine. Also, it would hardly make sense to indicate that the person's alone then note there's 20 enemies but it might be shadow clones.