Well you see, yordles are social creatures. Solitude brings out their worst. They NEED to be with their own kind to maintain sanity and happiness. This is why some Veigar mains see Veigar as not just evil, but full on crazy. The only reason Teemo isn't a complete psychopath is because he has Tristana. I don't really know about objects, but yes, friendship can help them a little. But you have to remember, basically all yordles (Except
and
) hate humans and see anything other than yordles as a possible threat, so it would need to be a friendship with another yordle if nothing else. and that would be a problem because bandle city hates conflict and tries to avoid it by keeping out the "corrupt" yordles. This is half the reason Kled stays in Noxus. And as for bringing them back to good after they go evil- you probably could but it would take a long, long time.