The elevator up to Ultraman's apartment seemed interminably slow. The building was empty, of course. It had been designated a hazard to be anywhere near the Kryptonian since shortly after he'd killed the police officers. But now two people were there specifically to meet him. The two people he'd most like to kill, and they were delivering themselves to him. But they had an advantage- the element of surprise, in multiple ways. Surprise that someone would even try to attack him, and surprise that they had a way to make it work.
Kara had a dagger hidden on her person, one that, if it came into contact with Ultraman, would stop his cells from being able to absorb radiation. His powers would slowly fade until he was just like everyone else, and would finally stand trial for his actions.

It was nerve-wracking for both of them, and they would be worried about Ultraman hearing their heartbeats, except that every visitor he had presumably felt the same way. In a way, they were lucky. No-one would think to check them for weapons, given that no-one thought any weapons could hurt him. It was perfect.

The door to the corridor opened and they were met by an assistant- a buxom brunette that greeted them with a completely false smile. "Welcome, Mr. Luthor! This way, please."
Kara was posing as Lex's aide, and wore clothes that were smart, but not too formal. Lex was wearing a suit, but then he'd been wearing suits all along anyway.

When they reached the apartment, they were surprised by two bodyguards, who stopped them. They were both large, muscular men that were intimidating even to Kara, though she knew they stood no chance against her. "Hold out your arms, please," one instructed them.
Kara's mind raced. They wanted to search them? But why?
Lex replied, "Is that really necessary? It's not like we can hurt him."
Ultraman appeared behind the bodyguards. "But that's not really true, is it?"
Lex and Kara looked at each other, and Kara reached behind her while simultaneously pushing her way through the bodyguards. She readied the dagger, and Ultraman waited until she was close, then dodged to the side and shoved her, pushing her into a wall. While she was recovering, he punched her, hard, in the face. Her head slammed into the expensive wood panel of the wall, splintering it. The punch made a loud crack, like thunder. He hit her again, and again, and when he was done she tasted blood and collapsed to the floor, dazed. Ultraman grabbed the dagger from where it had fallen, then kicked Kara in the face. Not done, he grabbed her by her shirt and dragged her back to the bodyguards. They held her up by the arms. Ultraman told Lex, "You shouldn't have brought my cousin into this. But I suppose it would have happened sooner or later."
He grinned at Lex, then in one smooth movement, swung the dagger, which cut through Kara's throat. Blood fountained from her, and Ultraman stepped back to avoid it getting on him. He watched her eyes widen as she realised what he'd done, and then as her life flowed from her, close. Ultraman nodded to the guards, and they released her. Slowly, a pool of crimson formed around her body.
Clark cocked his head to the side, listening, then after a pause told Lex, "And... there. It seems I'm the last of my people."

Lex didn't bother making any futile moves to try to hurt him. He just tried not to look at his friend's body, growing cold on the floor. She was so promising, both for defeating Ultraman and for everything else about her. A mixture of emotions and thoughts coursed through him. Anger at Ultraman for killing such a wonderful person, anger at himself and guilt for endangering her, and despair for what this meant for any efforts to defeat his enemy.

Ultraman told him, "For what it's worth, this was entirely your fault. You got her killed, attempting to kill someone who is just plain better than you in every way. You never stood a chance. And now, I'm not even going to kill you. I could, of course. But I want to watch you suffer, as you live every day, locked up, knowing that you were the one person with a chance of defeating me, and you screwed it up. I knew about your stockpile of everything that could hurt me. I kept a close eye on it as you gathered everything you could. Anything that could hurt me, all in one place. What a fucking idiot. You think I didn't know about Kara? You think my father didn't know that his brother was planning on sending his daughter to Earth? He told me everything. Or his projection did, anyway. I didn't know about Kryptonite, though, until you gathered up every scrap you could find so you could test it. And then, of course, my agent in your facility told me it could actually hurt Kryptonians."
He frowned like he was trying to remember something. "What was her name? Laci? Don't remember. Not important. Point is, I've been ahead of you from day one, and you've delivered admirably. Thank you for ridding the world of anything that can hurt me."

He made a motion to the side with his head, and the bodyguards grabbed Lex and hauled him away.

The police had been called. Everything "by the book". Lex was thrown in the back of a truck, which started off through Metropolis. It was getting dark now, and that combined with it being a Sunday night meant that there was virtually no traffic on the roads. The driver and the guy in the passenger seat didn't know what was going on. They knew the building they'd come from, because of the spraypainted "U" symbol on the side that warned people to stay away. But they didn't know it was Lex Luthor they were transporting. They would only find out when they got to their destination, and found out that he was the first prisoner they'd transported who'd disappeared during transit. The officer sitting with him was unconscious.

The only thing he would say when he woke up, was, "The Bat. The Bat!"