AU where Unalaq forces Mako to merge with Vaatu, knowing that Korra will be reluctant to fight her friend to the death. (Tumblr prompt)
"Kor-Korra!" Mako coughed out, but his desperate attempt to yell for her failed as Unalaq began to crush his body into the Earth.
"Unalaq! Don't you realize what you'll be doing?!" Korra said as she tried to hold her voice steady.
"Oh avatar, I think I do!" Unalaq replied wickedly. He firmed up his hands, making the Earth cave in more.
Korra looked at him wildly, then heard Mako's...shouts...his... yelping for her. She began to sprint towards the big opened up cracks of the Earth's surface, which inside layed Mako. Each step felt heavy to her. He looked farther away each time her feet placed themselves on the ground.
Was she running backgrounds?
"It's already late, anyways!" Unalaq stated, looking straight into her eyes. "Vaatu's in him. Stealing his mind and soul every second of now."
"But...why-" Korra paused, "Why would you..."
Unalaq scoffed at her and give her a pathetic look. "I don't want to get killed. I already know that if I'm connected with Vaatu..." Unalaq began simply, "that'd be two birds and one stone. Vaatu and I, together? No! But if he's in Mako, somebody...you don't want to kill...than perhaps you can't kill Vaatu either."
Korra's eyes and brows tensed as she clenched her jaw. "How dare you do that to him-"
"Ah! Enough chit chat!" Unalaq advised as...some...Mako Vaatu came out. Korra could still see Mako, the Mako she loves, in his eyes still. He wasn't completely gone...
"M-ako! What..." Korra began to felt herself shake, she felt herself...tremble.
"Kor-" Mako tried to speak but Vaatu began to overtake him more.
Korra threw a weak punch of fire at the Mako Vaatu, but failed to attack furthermore.
"You...can live...without m-e, ri-ght?" Mako, the real Mako, managed to spit out in quite difficulty.
"I...I don't think I can, Mako..." Korra confessed, tears spilling from her eyes, rolling down her cheeks.
"You're..." Mako began to struggle again as Vaatu began to take over his mind faster and quicker. "You're going to have to!"
"I can't hurt you!" Korra screamed.
"Kill me. For the world, kill me, Kor-"
Korra's eyes widened as his words faded and the color in his eyes went away. She clenched her fists in anger and with each slow punch of fire, earth, water or air, a tear fell to the ground.
She could've sworn she heard him say "I love you"