The Imperial Artifacts.
First of all, we can 100% assume that the group will go after them.
Now, they already have the ring and dagger. The ring gifted from the Sulrothums, the dagger stolen off Jornak's corpse.
They can probably pop over to Blantyrre and deal with Violeteye fairly easily. They've done it before. So now they have 3/5.
However, Zorian gave Oganj the orb and crown to bribe him to piss off. Daimen will lose his fucking mind when he finds out and Zorian will just be like: Chill, we'll go get them soon. Kill the dragon mage and take them off him. Duh.
Zach will light up at the mention of a fight but will then be like: ... Zorian you do realise how difficult of an opponent Oganj is, right? I mean, I've only been able to beat him once and that was in a timeloop where I could predict his moves and just try again if I die. Plus he now has the crown which will make his already ridiculous mana reserves even worse.
Zorian of course, won't just give in. He wants that crown and he did promise that Zach could have the orb. Plus Daimen will not let it go. So he'll probably be like: Chill. Give me a few months to prepare and we'll get him.
And so you have Zach, Zorian, Daimen, Alanic and Xvim facing a strengthened Oganj. Except Zorian also brought Princess, Mrva II (which he mentioned he will make airborne), a bunch of other golems, a bunch of grenades and other ridiculously overpowered stuff, plus his defense cube formation. Perhaps even the Sulrothum and their worm thing.
It will still be an intense fight but like, they have two time travellers, one of which is the strongest battle mage in the world, and one of which is a master golem maker and artificer, a prodigy that can make a huge combat avatar, a battle priest that has crazy fire magic, plus a guy with utterly ridiculous shields. Plus a God-touched hydra. Not to mention Zorian's simulacrums backing them with guns and stuff (leaving the mana reserves to the original). And like I said, they might even enlist help.
However, it would take time to get ready, because Zorian needs money to make these things and that... might take time. Plus they need to keep up appearances.