I’m Luke Summerhayes and I love Klefki.
I’m quite an absent-minded person. This leads to me being clumsy – knocking things over, dropping them and so on – and forgetful, whether it’s with a message I promised to send at work or where I left my wallet when I need it right now. It’s very frustrating at times, and it would be nice if there were some sort of creature or entity on whom I could pin the blame.
Historically, and even today if you go on the right internet forums, people blame fairies for the theft of missing objects, be that money, socks, or even keys. It is perhaps one of the behaviors fairies are best known for, so it makes sense to see it in the generation which introduced the fairy type.
Klefki is a steel and fairy type Pokémon which resembles an animate keyring, its head topped with a key-like horn and four other keys dangling from its loop.
Ultra Sun
Although it's unclear why it collects keys, giving it a key makes Klefki very happy. However, it apparently only likes master keys.

Klefki’s designer, Mana Ibe, said that Klefki’s inspiration was the keys one imagines in old castles and manors. With kalos being our first Europe-based region, it makes sense to have a set of keys for adventurers to collect.
Violet
In the past, noble families entrusted their vault keys to a Klefki. They passed the Klefki down through the generations, taking good care of it.

Ultra Moon even explains how Klefki lived before keys were invented!
Ultra Moon
Long ago it lived in mines, but once the minerals that make up its diet became scarcer, Klefki began appearing in human settlements.

The name Klefki, as well as the similar Japanese Kleffi, combine the French Clef and the English Key, both words having the same meaning. Non French-Speakers may have heard the word Clef in the world of musical notation, and Klefki does have some design elements similar to musical notation. Indeed, we might also use the English “key” in terms of sheet music or piano keys.
X
These key collectors threaten any attackers by fiercely jingling their keys at them.

Actually, Klefki can do a lot more than jangle keys threateningly. Despite its diminutive size and quite low stats, Klefki’s strong typing and prankster ability, which gives it priority when using non-damaging moves, allow it to cause genuine mischief in battle, paralysing, poisoning and laying traps. This behavior doesn’t achieve much in videogame two-on-two matches, but it can go a long way in the monster-switching world of single battles.
As with all Pokémon inspired by inanimate objects, Klefki has come under scrutiny from some fans. I think it’s a valuable addition to the initial reveal of the fairy type, and I hope it goes on trolling players for years to come.
Music for Luke Loves Pokemon is by Jonathan Cromie. Artwork for the show is by Katie Groves. If you enjoy the podcast, find out about my other shows at podcastiopodcastius.org, get in touch on bluesky @podcastpodcast, or support the show at patreon.com/podcastiopodcastius.
I love hearing from Listeners! Up next are Phantump and Pumpkaboo, so hit me up about those or any other Pokemon. Even if you don’t feel like doing any of that, thank you so much for listening.
I love Klefki. And remember, I love you too