I write way to much but hey! Please enjoy my take of what would happen if Artemis really died! Sorry if anybody is OOC!
Mind Link
"Welcome back." Kaldur said stabbing the sword in Artemis. When the sword came out blood poured out the stab wound.
"Artemis!" Nightwing screamed. He ran and caught here. "I've got you. Hang on." He slowly set here on the ground. He felt no pulse.
The rocket blew up behind them, as Nightwing has started CPR on Artemis. "We are done here" Kaldur said. Kaldur and the Manta Troopers left.
the the Bioship landed, Superboy jumped out and rushed, while Miss M jumped out of the water and came over.
"I don't hear her heart beat" Conner said.
"28. 29. 30." Nightwing said in a panicked voice. He did mouth to mouth. But nothing worked. Nightwing didn't want to say it but he had to "She's dead."
Nightwing sat down. Silent tears trickled down his face.
Miss M looked down and started crying as well, did Conner.
They sat or stood there. Then Conner picked up her lifeless body and carried it to the Bioship. Miss M followed wiping the tears. Nightwing looked down at his hands covered in her blood. He wiped his tears n his sleeve and was the last one of the ship. Miss M took the helm and drove the Bioship back.

Not only did they lose Artemis but the Light had Lagoon Boy.
How could things go so wrong, Nightwing thought, it is all my fault, just like the training exercise.
Megan noticed how much guilt and sadness coming from Nightwing. Conner and I will need to see if he is ok later she thought. She was so upset though Kladur had killed her best friend, her sister! They also took her boyfriend, Lagoon Boy. bConner felt so sad. He lost a member of his family! How could HE!
When they reached The Cave, Nightwing went to the Zeta Beams to go tell Wally and change his uniform.
So Conner carried he body to the Medical Wing while Megan told everybody.
It was a long sad walk for him.

The whole team was present (minus Nightwing and Conner).
"Guys" Megan said.
"Yeah" Karen said.
"The mission we went on was a failure and a sad one." She sighed. "Kaldur killed Artemis and Captured Lagoon Boy." Their were gasps heard. M'gann morphed her clothes into civves and sat down on the couch and cried.

Conner returned and leaned on the wall. He almost went to comfort M'gann but Beast Boy went up to her.
Then
Mal and Karen came up. "Where is Nightwing? He should be here!"
Conner sighed "He went to tell Wally" Mal and Karen exchanged worried glances.

Nightwing went home to Bludhaven and changed into a new costume. The he Zeta beamed t Pa Alto. He knocked on Wally's door. Wally answered "Come in" He said. When he shut the door he asked "Where is Artemis?"
"Kaldur killed her" Nightwing said feeling tears sting his eyes.
"WHAT DO YOU MEAN HE KILLED HER?!" He screamed, I SHOULD HAVE NEVER LET HER GO! THIS IS ALL YOUR FAULT!" Wally threw a punch at Nightwing right in the face, not even caring when he saw blood start coming from Nightwing's nose.
"I know it is all my fault" Nightwing whispered. "I wish it was me, not her."

"So do I" Wally said his voice dripping with venom. "NO GET OUT!"
Nightwing left, his tears flowing.
Wally went and sat on his couch, head in his hands. His dog came up and licked him. Wally put the dog in his lap and held him tightly.

Nightwing Zeta Beamed to the cave. Megan floated over and gasped when she saw his bleeding nose and tears streaming down his face. She went in an older sister mode like when they first started and he got hurt or sick.
"Nightwing," she asked sweetly, "What happened?" So he told her. "Let's get you patched up."
When they walked past, Conner looked worried at his leader and little brother. M'gann explained to everyone what happened, because she could tell Nightwing didn't want to tell the story again.
The Team (minus M'gann, Conner, and Batgirl) had never seen their leader so broken. Barbara got his nose to stop bleeding and hugged him comfortingly.
How could Wally be so mean, Batgirl thought, I understand he loved her, but Nightwing has lost so much more, and carried so much guilt.
Nightwing can Conner and I talk to you in private?. M'gann asked.
Yeah He said.
"Are you ok?" Megan asked.

"After all the people I have seen die, I don't think I will ever be ok." He said voice thick with sadness.
Megan walked up and hugged him tightly and Conner joined in.

"Thanks." Nightwing whispered. "I needed that from you guys."

"Nightwing, I will go tell Artemis's mom for you, ok." Megan said.
"Okay" he said.
Everyone else soon went to bed and so did Nightwing. Bludhaven would have to live without him for tonight.

"You have performed well my son." Black Manta said.
"Thank you, Father" Kaldur said.
"The rest of The Light will see you now." Black Manta said.
They walked toward the room.
"So, your son was able to kill Artemis, a former teammate. Impressive." Vandel said. "Welcome Kaldur'ahm! To The Light.

"Thank you" Kaldur said.

I hope you liked it! Please review!