This is really annoying - I've checked a lot online and see that the fuse Justiciar mission should be retroactive - but it is not in my game! I fused him a LONG time ago, and I also fused Relic Keeper, and I use Relic Keeper a lot - so why does this mission not unlock for me? It will take me so long to farm these champions again and fuse it all over again - so please help me fix it! 

Account name: Teovina, I am currently level 51, soon to be 52. Thank you so much for your help!