Okay so I got two Jhin mastery tokens for Jhin right. I don't have blue essence nor a Jhin shard but I own Jhin from buying him when he came out. But when I do the two tokens and Jhin permanent it won't let me unlock it. Are you serious I have to go boxes and keys and hope I get Jhin shards or get blue essence?
You can get "champion permanent" by owning all champions, then rerolling 3 champion shards. It'll give you a champion you already own, obviously, and it stays in your inventory because you can't use it.
You can buy the Mystery Champion Shard item from the shop for 1700 IP now, though. Buy a few of those, disenchant the results, and you'll have enough blue essence.
a jhin permanent is a his box opening shard
