All (in my opinion) potential Jax recruits

This is based off of champion without a very large focal point in the lore. (E.g. A lot of Ionian champions wouldn't want to be fighting a war on the other side of the hemisphere, especially since they wouldn't want to leave Ionia in case of another Noxian invasion.)

An adventurer at heart, imagine he totally wouldn't help Jax solely for the purpose of all those hidden treasures in Icathia Wants to take vengeance upon the void for taking his daughter and wife. Seemingly also searching for Kai'Sa, maybe relieving the Void's main home from it's infestation could aid in this mission. Hands down the most probably candidate. Has experience with a void-born. An ultimate hunter could be convinced to fight the ultimate swarm of monsters? If the runes were kept safe, surely Ryze would consider helping Runeterra by defending against the void? Although Jax and Zilean have no explicit connection aside from their city, and we have no idea if Zilean actually has a material form, if he did, he would 100% join Jax to fight. This one is a big stretch for me, I almost didn't put him here, but his connection to Taliyah and his loneliness might push him to seek honour outside of Ionia There's a theory that Taliyah is descendant from the thaumaturges of Icathia, maybe her sense of ancestry would compel her to help? If not for this, for her pride in protecting Shurima from the void. Although pre-occupied with restoring Shurima, defending it from the Void would surely be high priority. $ $ $ $ $ Rammus is a being question mark, he's considered a legend. But it would make sense if he was some sort of ancient protector of Shurima. One of his most loved people, Setaka, was felled at the wake of the Void. Surely he would want to avenge her. Even though if it is for the city they were at war with. Only put her here because of Jax's story. The Marai might want to rid their oceans of this power...

Very speculative possibilities:

This one is interesting, because Swain has a duty to Noxus, and a scourge of the Void is quite threatening. Although if he helped, surely the Black Rose would sieze power. Would he allow it? First Shurima then Bilgewater, Icathia could use a fleet or two. Diving intervention