*Not native

I see that some people are divided between the "He didn't do anything" and the "IDGF if he didn't do anything, Riot at least awknolegde his existence and put him on the cinematic".
Even if, in fact "he didn't do anything" I don't think that he would appear if he wouldn't be relevant this year (At least in the lore). I have some time without reading the lore so I checked what is, in my opinion the best lore channel in my language and this is what they said:

- He's forging in his mountain (I read some people saying that he was in another place)

- The last time the we knew some canon about Ornn was in the story that was dropped in his launch. In this story he was supposedly dead until some people that were scapping from Sejuani's tribe find his mountain and he saves them.

- Now we jump to the story that was drop recently, the one with Sejuani as protagonist chasing a mammoth
From that slaughter (The point above) only survived one man (Now a blind old man) that presenced the return of Ornn and he tells how he drank a little from Ornn's cauldron and didn't had hungry for months. This point is key because it explains the appareance of Sejuani on the Cinematic.

- That story tells that Sejuani's tribe is having the worst crisis hunger they have ever had. Their life physolophy don't support the idea of go to the south and live from the agricultory. Sejuani considered that old man crazy but after listen to him she though that the they're best opportunity is to find Ornn's cauldron and eat from it.

- The problem is that the mountain is custody by the shamans that praise Volibear (The ones in the Cinematic, Volibear is the clouds throwing thunders). That's why they're fighting in the cinematic, Sejuani propose to Olaf a crusade against the shamans to find Ornn's Cauldron.

- Ornn appears but don't do anything because people from Freldjord don't believe in his existence and the ones that did, think that he was murdered by Volibear some time ago, but we know that he was just living alone in the mountain after the slaughter of his tribe which have been foretold that they would come back to fight in the war against the Vigilants