Born the son of Ares and an unidentified mortal woman, Alexander Aaron was born a mortal and not a demi-god. The divinity within him was awaken by consuming the immortal blood of Amatsu-Mikaboshi over the period of several years. His emerging power identified him as the new God of Fear, so he took the codename of Phobos after the previous one.
Alexander was created by Michael Avon Oeming and first appeared in issue 1 of the Ares: God of War limited series, which revamped the character of Ares as an anti-hero figure in the Marvel Universe. Alexander played a central role in this revamp, serving as the reason for Ares to be less of a villain than before. Phobos had however already appeared in a different state in Doctor Strange 32, his first original appearance.
The character was later adopted by Brian Michael Bendis and Jonathan Hickman as part of the primary cast of the Secret Warriors ongoing series, which developed him as the new Greek God of Fear.
Major Story Arcs
Son of War
Alexander Aaron was born from a mortal woman in Dover, New Jersey and was the son of Ares, who had turned his back on Olympus to live as a mortal and raise his son. Alexander was raised by Ares alone without his unidentified mother. Still a child, Alexander was abducted by Zeus to use as leverage to convince his father to aid Olympus in a new conflict against the foreign god Amatsu-Mikaboshi. Before Ares could rescue him, he was taken from the Olympians by Mikaboshi.
Years passed in the realm of the gods, and during this time, Alexander was under the care of Mikaboshi. With Ares now among the Olympians, Mikaboshi wanted a countermeasure and that was Alexander. It was the Greek way for sons to kill and replace their fathers. This was what Mikaboshi had in mind. Alexander was fed blood, educated in his father's horrific history and trained in the eastern arts with the sword. When ready, Mikaboshi gave him the powerful Grasscutter sword.
In the final battle of the war, Alexander finally faced off against his father with the Grasscutter and all Mikaboshi had taught him. Nothing Ares could do or say succeeded in fully breaking Alexander from Mikaboshi's brainwashing, and Alexander ran Ares through with Grasscutter. Meanwhile, Zeus was in battle directly with Mikaboshi, and with the last of his strength, Zeus reached out to clear Alexander's mind. Alexander was horrified over his father's bleeding body, and while Mikaboshi gloated to the losing Olympians, Alexander struck him down with Grasscutter and turned the tide of battle.
Ares was soon reborn, and father and son soon returned to their mortal lives on Earth.
For further details: Secret Invasion
Alexander resumed living a normal life even while his father joined the Mighty Avengers. However, that changed the day Daisy Johnson found him. It turned out his name was on Nick Fury's list of Caterpillars, superhumans who had yet to be discovered by the world at large. It was explained to him that his new emerging abilities stemmed from the fact that he was to be the new god of fear. He was the new Phobos, and he took that as his codename as part of the covert team of Secret Warriors Daisy came to recruit him into. As part of this group, he was trained in secret over the course of six months by Nick Fury under the impression that their objective was to combat the Skrulls' infiltration of Earth. However after taking to the front lines in Manhattan and helping stop the Skrull invasion, Alexander and the other Secret Warriors discovered that all of it was only practice and their real task was something else entirely. Alexander was now embroiled in a secret war with HYDRA.
Around this time, Alexander had fallen into conflict with his father over Ares' decision to be a part of Norman Osborn's Dark Avengers. Also, Ares had begun to suspect there was something Alexander was hiding. Ares followed Alexander to a meet with the Secret Warriors and discovered the truth. However, he was convinced to respect Alexander's choice of path and came to an understanding with Fury about it.
Early on, Alexander used his prophetic ability to give his teammates insides into their destinies. He told Yo-Yo Rodriguez that she would be hurt, but that Jerry Sledge would care for her and find himself as a result. He told Daisy that she would be one of the greats and Sebastian Druid that he would be the best of them. However, Alexander informed J.T. James that he would die, which was a sad prospect as the two would become friends.
New God of Fear
Ares came again for Alexander when the time came for him to stand before the elite council of Earth's pantheons and have his worth as a god be judged. The issue was that Alexander was an anomaly. He was still a mortal and not even a demi-god. Drinking of Mikaboshi's blood awakened the godhood of his father's blood within him. This was of some concern. But in the end, he was welcomed among peers as the new God of Fear. It was not all celebration, though. Ares informed him that he was not yet a true god and would not be until he died a mortal death and was then one day reborn.
For further details: Siege
Though the Secret Warriors answered Captain America's call and took part in defending Asgard from Osborn's siege, Alexander was left behind. He was not present to witness Ares' death at the hands of the Sentry. In response, Alexander stormed the White House. He used Fury's access codes to get inside and fought his way through legions of Secret Service to get to the Oval Office. The president was evacuated before Alexander could reach him, so Alexander left a note in the Oval Office. The note blamed the president for Norman Osborn's actions and the death of his father. He warned that the president better learn from this, or someday, a god would not look on him kindly.
Facing His Own Destiny
Over the next six months, Alexander continued to be one of Fury's operatives, fighting a secret war against HYDRA and Leviathan. Hostilities just continued to escalate, and Fury decided it was time to launch a desperate attack on the heart of HYDRA. The plan was for the Secret Warriors to breach the security of Gehenna, HYDRA's principle base, and set off an explosive that would drop the mountain down on top of it. However, the operation would not go as planned due to J.T. being blackmailed into informing on them to HYDRA.
The infiltration was a success, but HYDRA forces prevented them from making their planned escape by neutralizing Eden Fesi, the team's teleporter. Alexander's prophetic knowledge allowed him to tell Fury where they needed to go in order to escape, and the team fled into the caverns around Gehenna. A stone bridge collapsed along the way, cutting him and Fury off from the rest of the team with HYDRA closing in. Fury shot a grapple line to get them both across, but Alexander kicked him, forcing him across the chasm alone. He knew this was how it was supposed to be and how it was always going to be.
Alexander faced off against HYDRA, but only the Gorgon stepped forward to confront him. Gorgon had long wanted to kill a god and viewed Alexander as that god since the first time they met. He also wielded the Godkiller, the counterpart to Alexander's Grasscutter. The two clashed with Alexander holding his own against the notoriously deadly Gorgon. Then, the blades of their swords broke against one another's. But Gorgon brought Alexander down with a body blow and delivered the killing strike, stabbing the broken blade of Godkiller down into Alexander's chest. Alexander met his end saying this was how it was supposed to be. He then awoke in Elysium Fields where he was reunited with his father.
Powers and Abilities
First and foremost, Alex has the ability to both discern what the greatest fears of his opponents are, and instill those fears with incredible accuracy against his opponents. For instance, when he briefly used his abilities on his uncle Pluto, he was able to discern that teddy bears and rainbows and boy bands were all fears of the death god, and used this to torture him until Amadeus Cho was able to gain access to Hades. When he used this ability against Norman Osborn, he was able to tell that Norman's greatest fear was his empire falling apart. This also seems to tie in with his ability to see the future, as he foresaw that Norman's interference in the plans of Nick Fury would accelerate the fall of HAMMER and Norman's empire as a whole. He was also able to see the futures of all of his teammates. It's unclear exactly how far or exactly how accurate all of these readings will be however.
Alexander is also an excellent physical combatant, having been trained by Ares himself. He was easily able to take down the President's entire security force at the White House during Siege, and this could indicate enhanced physical abilities such as agility, speed, and possibly strength. He was also easily capable of lifting Ares battle axe.