it’s not as bad as it seems, he’s actually one of the better nemesis
just be glad you’re not trying to farm Benji or Valde directly, now those are bad 
step 1, portal to ruins of Abyd, quick check outside spot, then run in the tomb, go through kill boss on final floor in tomb
portal to infernal wastes checking his 3 spots south of that, kill doggo boss and check for the Treasure trove too (spawning in 1 of 3 spots)
portal back to infernal waste spot, run north, check if totem is there (should be able to see it without actually taking left “fork”) - run into Tomb of Sethan and through it, killing Sister Crimson on the way ofc
^exiting the other side of Tomb of Sethan, running north to Scorpion tomb - inside and kill Scorpion boss (bonk totem on the way if spawned)
portal to Korvan City, - (check pink star if he shows on the map slightly north)
run south to check his spot, maybe totem, then inside Tomb of Nephos - grab Treasure Trove inside while there
portal to Eldritch Gate (Korvaak portal) run through the Astral Fields, kill Korvaak
portal to tomb of the Eldritch Sun, go through floor 1+2, kill Brother Segarius on the way + finish killing Kymon,
remember Treasure Trove on floor 2
final leg, portal back to Korvan City rift
run to purple star - should be able to see on map if Kaisan is spawned in the point with Dravis; if so run there and kill Dravis+Steward
if not, run to pink star, if he didn’t spawn on the way you now know he spawned inside Sunward Spire, run in there, finish killing Sunherald + reset
(grab treasure trove + totem on the way, possibly consider the side trip to Messenger if you don’t have Okaloth Helm yet/want Eldritch Essence or a Messenger Repeater build)
PS. this might seem like a “long” route, clearing everything on the way + checking all his spots, but it doesn’t actually take that long, and results in a sht ton of loot due to the amount of bosses and treasure troves or potential totems on the path