A lot of players hit Akthi and Anundr in The Khari Crossing Interlude and think, yeah, maybe this optional fight isn't worth the hassle. That's a bad trade. The reward is a permanent passive point, and in a game where every edge matters, that's huge. If you've already spent time farming gear or PoE 2 Currency, it makes even less sense to walk away from a free boost to your build. The fight feels rough not because one mechanic is unfair on its own, but because both bosses keep asking different things from you at the same time.
Why Anundr has to go first
The biggest mistake people make is spreading damage across both targets. It feels natural at first. They're both there, both dangerous, so you try to manage them together. Doesn't work. Anundr is the real problem early on. His damage may look manageable, but the arena gets worse every few seconds he stays alive. Quicksand slows you down, poison patches start covering your escape routes, and suddenly Akthi's pressure becomes much harder to handle. Burn Anundr first and the whole fight gets simpler. Not easy, just cleaner. Once he's dead, you've actually got room to breathe and read what Akthi is doing.
How to move without trapping yourself
This fight is mostly about movement discipline. Not speed. Not panic dodging. Discipline. You'll do better if you circle the edge of the arena in a steady loop instead of zig-zagging around like mad. Keep both bosses in view as much as you can. If one drifts off-screen, you're asking to get clipped by something you didn't track. A lot of deaths happen because players roll too early, then land in quicksand and can't get out before the next hit lands. Save your dodge for the moments that matter. If you see the ground getting crowded, rotate to cleaner space before it becomes an emergency.
What to fix before going in
You don't need a perfect build for this fight, but you do need to respect poison. Armour won't carry you here. If your resistance setup is weak, you'll feel it straight away. Bring a flask that can clear poison if you've got one, and make sure your mobility skill is on a comfortable key because you'll be using it constantly. Damage helps, sure, but survivability is what gets you through. Once Anundr drops, slow the pace down. Akthi still hits hard with lunges, tail attacks, and venom shots, but she's much more manageable when the floor isn't trying to kill you too.
Finishing the fight cleanly
When it becomes a one-on-one against Akthi, don't throw the win away by getting greedy. Wait for her recovery windows, land a few hits, then move. That's really the rhythm. You'll notice her burrow patterns faster when the arena isn't full of clutter, and her projectile attacks are much easier to sidestep if you stay calm. This is one of those encounters where patience pays more than raw damage. Beat it once and you get a passive point that keeps helping your character long after the fight is forgotten, which is a far better payoff than sitting on something like Fate of the Vaal HC Exalted Orb and still leaving power on the table.