So far we had very few items with actual lore/origin/story and I was wondering why.
Good example are 
and I think it's great to have some hints through items, even if they don't tell much.
could be a relic of Elder Souma, given that its names suggest connections with the Wind technique (and it looks like a katana ofc)
I think they should add a line or two to items and give them more depths like 
the game can only benefit from it.
What do you think?[slayer-jinx-catface]
I completely agree. I'd love to see some story behind Liandri's Torment 
or Athene's Unholy Grail 
. What's up with these items? What sinister stories lurk behind them?
- 
book or 
book (my theory)
In honesty it's only the art that seemingly (or misleadingly, depending on your view) connects into the universe. Which at best the art is only referencing unique traits prior established from the lore/world building. This is a great way for keeping the League IP consistent with itself but it's not a sign of agency that confirm items are canonical. Items serve a gameplay necessity above all, so implementing lore and serving items to canon would open a threat of restriction same as implementing gameplay into lore.
However that doesn't mean you can't have theories for how might items belong in-universe.
