Which would you 6 star next?

Two areas I'm struggling with currently are GR1 stage 13, the first stage where you can win mythical gear. So I was thinking aoe mage... So Eona and Zelus are immediate considerations.

The other is N8-14, it's been rough and I think I need a strong tank.

Also, I can 2 key nightmare guild boss, I'd like to bump up the damage to make it 1 key to finally be able to have a chance at harvesting Divine Shards. So Salazar has been a serious consideration as well.