One of the things I've been struggling to do properly in my various games is have a rival or villain for the PCs set up so that the PCs respect or fear them without their having to be a combat involving the PCs. The reason for that being, well, fights with PCs tend to be rather fatal, and well, that's not always the best payoff for an NPC you worked hard on. It's also really bad for starting a story when the whole point dies in the introduction. Today, let's talk about that.
Killing Friendly NPCs is Bad
One of the common ways I've seen GMs set up villains - and that I've tried to set up villains - is through killing friendly NPCs. Allies of the PCs, loved ones, friends, parents. Parents for some reason are a common one. it's like if the player doesn't make their character an orphan the GM is happy to help.
However, I find killing friendly NPCs just makes the PCs upset. Sure, it means they want to kill your new villain and maybe that's good, but it's not out of respect. You don't establish an identity that the PCs respect. It's just another name on the list of a group of increasingly powerful murder hobos. Still, if that's all you want, then go for it.
Saving The PCs is Also Bad
Having the NPC come in and save the PCs is also bad. Sure, the PCs will recognize the NPC is strong, but it often feels forced and contrived so you don't get the same reaction. The person becomes a villain and there are reasons why to ask about, and people know the NPC is strong, but you don't get the same relationship.
Helping the PCs DOES Work
Much like the best villains, the best rivals aren't stronger or weaker than the PCs, they're just as capable. If you can have an NPC that helps the PCs but doesn't steal the show - let's them be the heroes, but still does their job. This can turn into someone the PC's respect. Of course, now you need to start turning the NPC against the PC - or vice versa - but having that history of comraderie, equality, and friendship can do a great job of getting the kind of feeling you want.
The One Who Got Away
If you have to go with combat, try to get the rival out of the fight. Try to have some fights the rival wins - this is best against a single PC or something like that - and have some fights where the PCs get the upper hand. Too many PC victories and the guy starts to look like a joke - which you can totally play into. Too many NPC victories, and it can start feeling like you're stacking the deck against the PCs - which can be a problem when the PCs earn those defeats by not thinking properly or playing their cards right.