A small oak chest floated through the seven seas for centuries. It contained little of significance, but it was the last hope of one woman to contact her sailor of a husband. It, of course, never reached the destination it was meant for, as he never received the letter and was lost in the tides. All the chest contained was a charm that the wife had hoped her husband would sport with pride. As a sailor for the country of Portugal, he and his family took great pride in the accomplishments he shared with the nation of sea-faring. The charm was a small boat shaped emblem, engraved with the message "Portugal - Greatest Power In The Seven Seas", in the native tongue of course. It had been lost for centuries, but now it landed within the city of Atlantis, far below the cusps of the sea. It was amazing enough that the chest had survived this long on the sea, but it was now inside Atlantis. A random citizen of the city found it, and realizing it from outside, immediately delivered it to the royalty. Atlantis as a whole was fairly xenophobic, and they especially didn't trust the surface-dwelling humans. Terrible people, the lot of them.
Most of the people within the castle were uninterested by the trinket, but it was an unfortunate circumstance that Namor the Sub-Mariner would find it. He was angry at one of the scholars within Atlantis, and in the midst of yelling at him noticed the emblem. He grabbed it from him forcibly, and took a closer look. After asking what it meant, he received the answer and was most displeased by the arrogance of the surface world.
"Greatest power in the seas, they say?" He snarled, eager to defend the honor of Atlantis. "No one insults Atlantis in this manner!" He commanded, stomping off to teach Portugal a lesson or two. He was not around to hear the explanation given by the scholar in vain.
"It's from centuries past!" The man called after Namor uselessly, hoping to prevent a full-fledged war. Namor paced around the city of Atlantis, angrily dwelling on the statement.
"They mock me and my state! They send this trinket down to taunt us! Do they truly seek this conflict? I will teach them the meaning of power. They've done nothing significant for decades! They cannot be allowed to mock Atlantis in this manner." He raged, finally deciding that he would teach Portugal better than to discount Atlantis. Without a second thought, he swam away, headed directly towards Portugal. The man that he had stolen the pendant from chased after him briefly, still hoping to get Namor to see the truth, but was quickly outran by the furious Avenging Son of Atlantis.
Some time later, the small medallion spurted from the water onto a dock in Lisbon. A citizen returning home from a long journey was the first to notice it, as it landed at his feet. He picked it up curiously and read it, still confused as to where it had come from. He peeked into the ocean in front of him, but backed away as the surface began to meet with turbulence. As he tried to escape from the underwater disturbance, the dock he stood on exploded before his eyes, and a figure rose into the sky. Debris fell around him, and he covered his head in hopes to avoid serious injury. The rest of the city paused as they noticed the assault, and they fearfully watched Namor in the sky.
"I will show you fools true power!" He growled, wanting the people to know why they were being attacked. Many of them cowered, but Namor continued to destroy the docks of Lisbon, mostly attempting to lure the military into a conflict. Before they arrived, he would simply focus on structural damage to them. The Atlantean picked up entire sections of the dock and threw them into the buildings surrounding. He tore apart the ships docked and destroyed entire sections of the infrastructure. The people were allowed to escape, if they were able to dodge the debris, and so Namor continued his attack until the military arrived.
It was mere minutes before the first jets were scrambled. Namor was disappointed by the challenge.
"I want to fight with the SEA POWERS of this pathetic nation!" He demanded as he flew at the jets. They attempted to gun him down, but he easily dodged this and tore the wing off of one. The pilot ejected quickly and landed safely in the waters below. As the jets turned to face him again, they decided to use their missiles on Namor. He smiled as he saw one come in his direction, and quickly positioned himself near it. As it came close, he reached inside the ballistic and tore a handful of wire out. It sporadically faltered until eventually falling into the ocean and exploding harmlessly. Namor grabbed another ship, still in one relative piece, and hoisted it high over his high. As the planes turned once more, they were surprised to be met with the massive vessel, and promptly knocked from the sky. As Namor praised himself for the act, he was surprised from behind by an artillery shell. It exploded upon him, not necessarily injuring him but certainly irritating. He turned to find himself greeted by a squadron of tanks, all aimed to take him out before he could reach them. They did not account for his extreme durability, but enough shots could indeed hurt him. Namor was still displeased.
"YOU ARE NOT WHAT I SEEK." He stated, falling underneath the waves. The tanks could attack him from the ground, and so he bided his time. As he grew weary of waiting, he positioned himself at an angle so that he would emerge from underneath the metallic behemoths. After even more boredom, and some time to recover strength, he burst from below. The ground itself shook from the impact, and he tore past a number of tanks and men as he went into the sky. One tank flipped onto another, and the men scattered to avoid being crushed underneath the impact. Before they had a chance to recover and aim at Namor once more, he came from behind a removed the cannon from one of the weapons. He flew high into the sky and spun it around before releasing it in the direction of another. The detached cannon he threw was met with a artillery fire from the defensive tank and deflected. They did not have time to fire again, however, and Namor crashed into the steel, piercing through it as the bullet from a sniper does the skull of a victim. Namor did not even bat an eye at the men still on foot, as they were less than threatening to his power. He would focus on them some other time. As he hovered over the crowd that had gathered, he heard something that demanded his attention.
"THAT is why I am here." He said happily, as he submerged himself in the water once more. He found himself threatened by a trio of submarines, with a large battleship crossing the horizon. He swam in place before the subs, confident in his ability to deflect their assault. All three fired at once, and the torpedoes they delivered to him hit with impact enough to destroy a dozen city blocks. Namor paused briefly and winced sharply.
"THIS is your power! You are an embarrassment to true warriors of the sea!" He commanded, advancing on the enemy. He swam quickly around the trio, quickly enough to cause a whirlpool to form around them. He did not stop for several moments, causing them to be swept in the waves below the surface. The centrifugal force was enough to handicap the men inside the ship, who could do nothing but hope he would release them. Eventually, he did, and they were shocked to find themselves still in one piece. Namor finished the fray by thrusting each of them from his ocean onto the shores of Lisbon, rocketing them from the waters and into the city itself. Now his last opponent was the large battleship, which he flew directly under and raised from the water. He flew over the shore of the nation he had attacked, and smiled as he overturned the ship, forcing all of it's content out and onto the ground. At long last, he dropped the ship entirely onto the city of Lisbon. He continued his flight above the city and spoke loudly and clearly, sure that all of the people heard him.
"This has been a lesson in humility. The greatest power in the sea is indeed IN the sea. If you forget this again, I will be forced to enact more serious measures." He declared, explaining his attack on the city. Now he hovered just barely over the surface of the waters, and sank underneath as he delivered one last warning.
"Do not make me return for this ever again."