This will most certainly be an incredibly strange ask, but I finished watching Predator recently, and was thinking, how would New Vegas or 4 companions react to having (with the help of their respective protagonist) killed one of them?
FNV Companion's Reactions To Having Killed One Of The Predators
Boone finds them disgusting and would want to send in a report to the NCR just so they're aware of what's out there. They're a threat to the natural order of things, and if the Legion got a hold of one, the Mojave would be screwed. If anything, he'd want to try and find more so they could be turned into weapons for the battle at Hoover Dam. The whole ordeal would be another reason for him to be kept up at night, too busy worrying over the possible dangers that could harm either of you to even want to rest.
Arcade would stand in shock, confused at what he was looking at, before snapping out of it and taking as many samples as he could carry with him. He'd try and take everything he could — from its weapons to syringes filled with its blood — just so the Followers could help research it with him. His biggest concern would be that more would eventually come, so he's hoping this will make everyone more prepared if they do.
They might not even realize Raul's alive at first, or at the very least, go a bit easier on him due to how sick he looks. He'll be glad when the thing finally dies, hitting it once more to ensure it stays down. He'll make bitter comments about how he 'doesn't even look that old'. He's more salty about it than anything, but he does try and recommend that you and him stick to NCR or Legion camps so they can deal with them if another ever comes back.
Lily is appalled by the lack of manners the Predators have and will give you this short shpeal about how you should never end up like them. Her schizophrenia makes it hard for her to fully comprehend this as a real event and not a sign that she just needs to take her medicine a bit more often, but she's there to support you when things go south.
Cass would start shooting at it the second it appeared and would feel so accomplished if you two actually did get it to die. She'd be exhausted afterward, suggesting that you guys set up camp for the night and figure out what to do with the beast in the morning. She might even throw some of its limbs on the fire to see if they're edible, and the armor would be good to sell...
Veronica would also try to gather as much information as she could on the creature and write a quick report for the Elder. This thing that the two of you killed is a technological marvel and she'd be damned if she let it go to waste. In fact, she might even ask you to help drag the entire thing back to Hidden Valley so that the other scribes can look at it in a more hands-on manner.
They can't see ED-E through their Bio-Masks since he doesn't produce any thermal heat, so it'll mostly just be the courier trying to kill it while he zips around in fear, trying to find a weak spot on it. It'll be more of a relief than a curiosity when you finally get him to fall. You'd probably just end up leaving it there and going to the nearest settlement with how tired the both of you would be.
Rex is still tense, even when the two of you do manage to kill it. He'll bark and growl until you're both far away from whatever hole you left it in and will be visibly shaken if you end up wandering close to the area ever again.
