While Jax's story is somewhat short, I do think that he will ultimately play a pivotal role in our fight against the Void, and to reclaim his homeland of Icathia.

Sources:

Grandmaster at Arms: https://universe.leagueoflegends.com/...

None Shall Pass: https://universe.leagueoflegends.com/...

Where Icathia Once Stood: https://universe.leagueoflegends.com/...