I did see you can forge them with blue essence, champion's shard or permanent champion, what is this last one?
Blue Essence: You get them by destroying champions shard
Champion Shard: As skin shard, you get them from chests or from the champion shard token
Permanent Champion: What is this? For example, I have Ashe mastery 6 and 3 tokens for Mastery 7 Ashe, ofc I have Ashe permanent, how does it work now?