This is the first of a set of Father's Day fics that I did from prompts for Father's Day in 2017. I'm finally getting around to posting them.

This first one was based on this prompt:
"five times Vader tried to mentally contact Luke and one time Luke responded (sorry if that's a lot; I just love the 5+1 format)"

Warning for major character death in this one, it is canon-compliant to the end of ROTJ.

The first time was only a few days after Bespin. It was nothing more than a cautious nudge against his mind, a tilt of the head across a crowded room in an attempt to make eye contact, but Luke still slammed his shields up. He was shaking, he realized, and he cradled his arm against his chest in an effort to alleviate the phantom pain. Wedge looked at him in concern, but Luke shook his head before his roommate and Second could even open his mouth to ask if he was alright. Luke tried to return his attention to the squadron progress reports in front of him, but couldn't make himself focus. He had hoped the thread he could feel connecting him to Vader would fade with distance and time, that it had been some trick of the Dark Lord's to lure him in, but he was beginning to realize that it was a part of him that had always been there. It had simply lain dormant in his ignorance, and no matter how hard he tried to convince himself that Vader had been lying, this… bond or whatever it was sat like a cold bonfire in the back of his mind, refusing to allow him to retreat into denial.

The second time was much like the first, and Luke tensed at the now-familiar brush against his mind, refusing to acknowledge it and pretending he hadn't even noticed the careful entreaty of "Son?"

Leia looked at him in concern, her brow furrowed as she mouthed, "Are you okay?" across the meeting table. He nodded slightly, not wanting to interrupt the mission briefing. Thankfully Leia was the only one who had noticed his lapse.

The next time, Vader was much more insistent. Luke had since realized the futility in denying what the Force insisted was true, but that didn't mean he had to respond. He ignored his father's requests to come with him and returned his attention to the finishing touches he was putting on his lightsaber. He didn't need the distraction of Vader's voice in his head while he was rescuing Han.

Coming with the strike team had been a terrible idea, Luke admitted to himself when he felt his father's questing attention land on him in the cockpit of the Tydirium. He didn't respond to his father's almost fearful curiosity regarding his presence in the Endor system, but he also didn't attempt to shield himself. There was no point, after Vader had sensed him. He knew it wouldn't be long before his father came after him.

The fifth time wasn't so much a conscious attempt at contacting him on Vader's end so much as a brightening of their connection that Luke realized meant his father was on the moon with him. It would not take Vader much time to find him, and he knew if he stayed with Leia and Han, the entire team and mission would be compromised. It hurt to say goodbye to Leia, his sister found and lost, and part of him wished he'd been successful in slipping away unnoticed. But she deserved to know, even if it was a truth she wouldn't want to hear. And when he never came back…

No, it was better they spoke one last time before he surrendered himself into his father's custody.

The last time his father's mind reached for his, he was no longer Darth Vader but Anakin Skywalker, and Luke allowed the contact, reaching back across their bond to bask in his father's Light. It burned strongly, beautiful and pure, defying the failing body it resided in. The shadows that had obscured it had been seared away by the intensity of Anakin's love for his son, love that now surrounded Luke and embraced him. And even as Anakin's eyes closed for the last time, Luke could still feel his presence next to him and knew he would always be with him.