User blog comment:DarkCreeper/The River King/@comment-5654809-20150619171755

His abilities (or at least one of them) will probably have something to do with the river itself, Riot has already confirmed that he has 3 passives in his kit, so maybe one of them gives him extra bonuses while in water.

As for the eating an ally or enemy ability that's been thrown around, maybe he grabs a champion and then carries them to a location. I'm thinking it's probably an ally only thing, maybe some sort of pact/deal similar to Kalistas passive. (though probably usable more than once)

This ability could be tied to the river, maybe he can easily teleport and carry champions up and down the river only.

It would be interesting if he could quickly help allies lane-swap.