Mark's power allows him to create bouncing orbs of light that can detonate either concussively (and largely nonlethal) or explosively with potential lethal force. He can adjust the charges to control the size of the resulting explosion and maintains a secondary power that allows him to ignore the effects of his own improvised weapons. He could create a large amount of explosions.
He was severly devastated by a brain injury, but was able to get around it thanks to Panaceas intervention.
↑Treating like a monster might be a little overboard, but they're accurate in reading scenes where Amy was neglected.
Carol's word choice is one hint here - you can read the interlude that was just covered and note how Carol refers to Amy vs. how she refers to Victoria. The words aren't hateful, but Amy is 'amy' and Victoria is 'my daughter'. She says, outright, "I don't want her" while the child is in earshot, and then when Lady Photon says "You could grow to love and trust that little girl, too.” Carol's (later, connecting) thought is "Liar".
Look at Amy's conversation with Gallant... "Carol never really wanted me. Mark is clinically depressed, so as nice as he is, he’s too focused on himself to really be a dad."
Interlude 11.h, It had always been Victoria, only Victoria, who made her feel like she had a family here.
Then later, same interlude, What Amy felt from her ‘mother’ was a chill. She knew that she was only justifying the darker suspicions Carol had harbored towards her since she was first brought into the family. It was doubly crushing now, because Amy knew about Marquis. Amy knew that Carol was thinking the same thing she was.
Carol didn't reach out, she wasn't warm, she wasn't a mother. At best, Amy was a person living in their house. At worst, Amy was someone suspicious, Marquis' daughter. So Amy never really had a 'home', a safe haven to retreat to. If you want to read between the lines, the fact that she'd go out at night to visit the hospital (and that nobody was stopping her) might indicate more about her feelings at home. She wasn't mistreated. She got fed, she got clothes. Mark (Flashbang) even tried to be a warmer dad when he was up to it, but that's something as rare as the sun coming out in the UK - brief and unpredictable bouts of good in the midst of a perpetually overcast setting. In the end, all she really had was Victoria. - Comment of RPR.net by Wildbow
↑ 2.02.1Flashbang, Mark Dallon – Husband to Brandish, father to Glory Girl and Panacea. Could create bouncing light orbs that detonated with concussive or explosive force. Suffered long term head injuries in the Endbringer arc, but was cured by his daughter. Wears a white costume with a green-yellow icon of an exploding grenade, complete with padding and a helmet. - Cast (in depth)
↑ 3.03.1Flashbang – Member of New Wave, Flashbang can create orbs of energy that bounce and explode with a measured degree of light and power. - Cast (spoiler free)
↑ 4.04.1Mark flicked his eyes in one direction, offered the slightest of nods, his forehead rubbing against hers. Amy flung herself to one side as Mark stood in one quick motion, flinging the glowing orb at the little girl.
Hack Job flickered into existence just in time to have to orb bounce off his chest. It exploded violently, tearing a hole into his stomach and groin. The villain flew backward, colliding with Bonesaw.
But two more copies of Hack Job had already appeared, and the scalpel spiders were responding to some unknown directions, leaping for Mark and Amy.
Amy grappled with one spider, struggled to bend its legs the wrong way, cried out as the scalpels and needlepoints of the other legs dragged against her skin.
A blast sent her tumbling, throwing her into the couch and dislodging the spider. Mark could make his orbs concussive or explosive. He’d hit the spider with the former, nothing that could seriously hurt Amy. She climbed to her feet, picked up the oak side-table from beside the couch and bludgeoned the spider with it.
More explosions ripped through their living room as Mark continued to open fire, hurling the orbs with a ferocity that surprised Amy. When Hack Job tried to block the shots with his bodies, Mark bounced them between Hack Job’s legs, off walls and off the ceiling. Almost as if he could predict what his enemy would do, he lobbed one orb onto the couch. It exploded a half-second after one of Hack Job’s duplicates appeared there.
More duplicates charged from either direction, and Mark dropped a concussive orb at his feet, blasting himself and one of the duplicates in opposite directions. He quickly got his footing and resumed the attack, fending off one duplicate that turned his attention to Amy, then going after Bonesaw.
Bonesaw had retreated into the hallway that led into the bedrooms at the back of the house, the basement and the kitchen at the side. Mark threw an orb after her, obliterating the hallway, but Amy couldn’t see if he’d struck home, not with the clouds of dust that were exploding from Hack Job’s expired duplicates. Between the time it had taken to create the orb, throwing it and the lack of a scream after it had gone off, Amy knew Bonesaw would have gotten away. -Excerpt from interlude 11h
↑Mark was in the living room, sitting on the couch. No longer able to don his costume and be Flashbang, Mark could barely move. He had a form of brain damage. It was technically amnesia, but it wasn’t the kind that afflicted someone in the movies and TV. What Mark had lost were the skills he’d learned over the course of his life. He’d lost the ability to walk, to speak full sentences, hold a pen and drive a car. He’d lost more – almost everything that let him function.
What little he regained came slowly and disappeared quickly. It was as though his brain was a shattered glass, and there was only so much he could hold in it before it spilled out once again. So they’d patiently worked with him, helping him to hobble between the bedroom, living room and bathroom. They’d worked with him until he could mostly feed himself, say what needed to be said, and they didn’t push him to do more.
Victoria was in costume as Glory Girl, but she was unclipping a bib from around his neck, something to ensure he didn’t stain his clothes while he ate. Amy’s adoptive father turned and smiled gently as he saw the other two members of his family. It was all Amy could do to maintain eye contact, smile back. -Excerpt from interlude 11h