What the achievement asks
Defeat all nineteen rare creatures found on K'aresh. Fifteen points, account-wide.
Not ten of nineteen. All of them, and most of them exist only in Untethered Space.
What you need before you start
Fourteen of the nineteen live in Untethered Space, the phase-dived version of K'aresh. Getting there needs the Reshii Wraps, which come from the K'aresh campaign, and you enter through the Phase Conduits dotted around the map.
You do not need the cloak upgraded for the rares. Rank 4 is only required to see treasures. Finish the campaign, take the wraps, and every rare below is reachable.
The Phase Conduits also work as fast travel inside the zone, which saves a great deal of flying once you know where they are.
The three in the open world
Malek'ta does not spawn on his own. Stand at 54.05 58.84 and jump, repeatedly, until he erupts out of the ground. It looks absurd and it is the actual mechanic.
Chowdar patrols the snowy outskirts of Tazavesh, on the Tazavesh map rather than the K'aresh one, running roughly between 71.99 81.89 and 81.74 74.27. Follow the route rather than waiting at a point.
Heka'tamos: four buffs, then the brazier
Click all four objects around The Oasis, then use the Brazier of Elemental Union to summon him.
Each buff lasts three minutes and you need all four at once. The route above is the efficient order, and if one expires you have to go back for it. Do not stop to fight anything on the way round.
The two behind Warrants
These two only appear while you hold the matching Warrant, and Warrants come from the weekly quest A Key Threat, which offers one of six each week. It is the same one for everybody on the realm, so alts cannot fetch a different Warrant and there is no way to force it.
That makes these two the achievement's real clock. In the worst case you are waiting several weeks for both to come round. Start checking the weekly the first week you decide to chase this, and take whichever Warrant is offered even if you do not need it yet, because the rotation is what you are waiting on rather than the kill.
The fourteen in Untethered Space
| Rare | Coordinates | Note |
|---|---|---|
| Ixthar the Unblinking | 63.82 43.63 | |
| Korgorath the Ravager | 66.31 42.58 | |
| Morgil the Netherspawn | 56.20 50.58 | Moves a little, stays in the area |
| Shadowhowl | 54.10 49.24 | Patrols the icy ground by Archival Assault |
| Revenant of the Wasteland | 50.53 64.69 | Interrupt Spirit Siphon or he heals |
| The Nightreaver | 52.62 56.18 | Patrols high in the sky, pull from here |
| Maw of the Sands | 54.45 54.45 | Elite, bring help |
| Orith the Dreadful | 52.77 20.64 | Elite |
| Prototype Mk-V | 45.78 24.25 | |
| Sha'ryth the Cursed | 72.15 55.29 | |
| Stalker of the Wastes | 76.75 42.19 | |
| Urmag | 70.14 49.83 | |
| Xarran the Binder | 65.14 49.98 | |
| Sthaarbs | 74.04 32.54 | Elite, reached through a portal |
Sthaarbs is the awkward one. Take the portal at 75.88 32.89 and use the Phase Warp extra action button to reach him.
Maw of the Sands hits hard enough to be worth preparing for. Check your bags before you pull: a Deployable Wind-Wrangling Spire gives you the speed to leave his pools, a Deployable Recovery Keg covers the healing, and Deployable Battle Supplies covers the damage. He casts Volatile Spittle and then Volatile Outburst, so run out when the second one starts and come back in.
When a kill does not register
Players have reported killing a rare, seeing the criterion tick, and the achievement still refusing to complete. Reloading, restarting and killing it again on an alt made no difference for them.
Check the criteria list rather than the kill count if you believe you have all nineteen: it is normally one of the two Warrant rares that is genuinely still missing, because those are easy to lose track of across weeks.
Where it fits
One of seven under Unraveled and Persevering, part of Worldsoul-Searching, the War Within meta. The treasures of Treasures of K'aresh are on the same ground, and every rare here pays K'aresh Trust reputation, which is what Bounty Seeker and the rest of the branch run on.