NPCs are a very important part of RPing. They shape a big part of the world. How do you treat your NPCs? Do you mind it if other people play as NPCs you've created? What are some good NPCs you have seen?
My important NPCs usually exist for the sake of plot development
when I'm not using Fox's for that. They quite literally exist to shape the world and the plot in order to keep things interesting and keep things moving. Due to this importance I prefer that other people consult me about the use of these NPCs and do not use them if they can't keep them in character. I also prefer not to play other peoples' important NPCs for the same reasons.
Throw away characters though I don't really mind. Do what you will because they don't have any real importance or effect in regards to the story.
My favourite NPC to write as is probably Clarity James from Begin Again. She's a very different character for me to play as and I find writing from her perspective quite challenging for some reason - although on both counts I can't say why - but I love the parallels and contrasts between her and my actual character and I'm going to enjoy shaping her into a great rival for Tasman.
I really enjoyed Klippy's use of an NPC named Effa in Begin Again also. She herself wasn't a hugely fleshed out character but the way he used her in regard to his main character is an enormous part of what made reading Klippy's posts so much fun in that RP.
I'm also loving the various NPCs that are coming up in Gunpowder. In particularly I'm extremely fond of Janet (I know I created her but I credit her great characterisation to the others, in particularly Sonata) who is an old retired bounty hunter who runs the agency beginning hunters work from. She's a cranky, naggy and mean woman for the most part but that's what makes her endearing. Ezekiel, created by MI, is another favourite of mine. He's an extremely powerful and extremely religious sorcerer who serves as a priest. The veritable mountain of NPCs created by Fox and Sonata throughout the RP so far are too many to mention, but they are honestly all great characters and in the case of many fantastic plot devices for me to play with.
Even though I haven't gotten my post up yet, honourable mention goes to Disco from Titans just because he is possibly the most hilariously awesome concept of a villain ever.