Question: How did others find the trident's location? We know Arthur is the first person to see the clue to the trident's location, so why are there dozens of skeletons of past victims, how did so many others magically stumble across the trident?
Question: Why does Aquaman even use a thing as a shield in the submarine when he is bulletproof?
Answer: "Aquaman" director James Wan commented on this when a question was posed about if Aquaman is bulletproof, how can he get tattoos. "Bullets (or whatever else) will penetrate and break [Arthur's] skin. He's not a man of steel. He just has really dense mass/muscles. At least that's what Geoff Johns and I talked about." In addition to his advanced resilience, he also has advanced healing abilities. Geoff Johns is a comic book writer whose work includes Aquaman, and he was President and CCO of DC Entertainment at the time. In the comics, Johns has shown Aquaman to be vulnerable to bullets.
Answer: Just because a bullet won't kill him doesn't mean he'll get hit by bullets if he can avoid it. It would still cause pain. He also isn't bullet proof, he is merely bullet resistant. Larger calibre bullets would hurt him.
Question: How did Atlantis evolve in 5 seconds? We are shown Atlantis being destroyed in under a minute, the entire area is underwater, how did they all suddenly breathe underwater? How did they sleep whilst they built underwater, did they just bob about like jellyfish? Why not head to land...and finally how did humans turn into crabs in under 2000 years?
Answer: People survived the fall. Atlantis was destroyed and many Atlanteans were killed but a lot survived the devastation and with their advanced technology were able to keep living and building in Atlantis. Some didn't, chose other methods, different homes. At first they used technology to breathe underwater but eventually they either evolved or developed themselves into water breathing creatures. The Crab people were Atlanteans first as well, but evolved themselves in more hostile territory, causing more elaborate changes.
Question: Why does Mera say Aquaman is king by birthright as he is the eldest? That's not how it works. He's not the King's first son, but the Queen's, and that is irrelevant.
Answer: Like King Arthur, he may have been born out of wedlock but had royal blood as his mother was of noble birth with kingdom of her own. She wanted to avoid any arranged marriage.
Question: King Orm is seen having trouble breathing in the first battle against Arthur when Mara helps him by putting an air bubble around them. How then in the final battle is he fighting on the surface with no trouble?
Answer: It surprised him and that's probably the first time he breathed in air in his life. The second time he was prepared.
Question: How old is Atlantis? They say king Atlan was in charge at a time when most thought the earth was flat, well that's less than 2000 years ago, however the Sahara has been a desert for a whole lot longer than that and it was said to be home to one of the 7 kingdoms, but them the Karathin says it has guarded the trident for 1000 years, so which is it? 1000, 2000, 10000?
Answer: No, Vulko said they had unlocked the secret of unlimited energy whilst the rest of the world still thought the earth was flat. Atlantis was already old by then, so it's definitely older than 2000 years. Atlan ruled over Atlantis for thousands of years. To say Atlantis is over 10000 years old is probably the most accurate.
Question: Why did Arthur need to go to Atlantis to meet Vulko? We see Vulko coming to the surface multiple times, would it not have been easier to meet Arthur on land?
Answer: Because what they're looking for is in the ocean. The maps, the ancient texts and markers leading to the trident. It would seem odd to search for Arthur on land then return to the ocean.
Question: There is something I don't understand about Arthur. Why is he so reluctant to be king of the undersea nation of Atlantis?
Answer: I agree with the other answer but would add that suddenly becoming the ruler of such a huge and diverse kingdom that he'd been detached from growing up and to then assume such an immense responsibility would be daunting. Being king means sacrificing your personal freedom in the service of others.
Answer: Because he felt abandoned, by both his mother and his people. He was considered the bastard of a human and mermaid, and, like an interracial couple, it was considered illegal and immoral. Why rule when you're not wanted?
Question: Why didn't they move? Surely they could've hidden in one of the other states mainly a landlocked one like Iowa, Nebraska, or Kentucky, as in not near an ocean.
Answer: Yes I mean as in his father and mother should've moved, not the Atlanteans.
They both obviously love the ocean very much, and it might have been to hard for them to live away from it. Call it a false sense of security if you will.
Answer: If you are talking about the Atlanteans, their entire civilization sunk into the ocean. Instead of leaving it, all that history, culture and technology, they adapted instead. They didn't want to leave their home and be exiled forever. A lot did go and live in other areas of the ocean but by that time humans had taken over on land, and they didn't want to interfere, nor did they need to by that time.
I think the question is asking why Arthur's parents didn't move. Why, knowing that people from Atlantis are hunting you, would you continue to live near the ocean?
Question: Did Aquaman kill all Black Manta's crew at the start? As far as I can see he just knocks them out, but they don't seem to leave. If they die, why is he so upset about the guy's dad, when he left a half dozen to drown?
Answer: As far as I can see, Aquaman didn't care if the pirates died, including Kane's father. When Kane begs Aquaman to help save his father, Aquaman just glares at Kane and says, "You killed innocent people" and abruptly leaves without helping. Aquaman then saves the Russian crew but leaves the sub and pirates to sink. All of this explains why Kane becomes Black Manta (because he hates Aquaman for leaving Kane's father to die). But, as far as Aquaman was concerned, the pirates got what they deserved.
Answer: It was an accident, while trying to stop Black Manta's crew, Aquaman's battle caused a lot of damage. Which made one of the bulk heads blow and pinned his father down. He believes if Aquaman had let them siege the submarine and not interfere, his father would be alive.
Little correction to the answer: Kane's father fired two mortar rounds in the sub's torpedo magazine (which somehow, amazingly, did not detonate the the whole sub). The first mortar struck Aquaman dead center without killing him and everyone else in the room. The second mortar damaged the torpedo rack, dislodging a torpedo that pinned Kane's father against the bulkhead.
Answer: You said it yourself some might have stumbled upon it, others could have used the map, which is why it was hidden in the first place.
How could they use the map when Arthur was the first to find it...quite frankly to stumble on it is impossible, you would have to randomly travel to the trench, go through the entire kingdom, see a tornado of death and decide to go in, get spat out and not eaten, get to shore, check behind a waterfall and follow it down...bit much?