- Strong Soul Arrow attack
- Strong Scythe swipe
First off, there are only three of these guys. However, being a personification of Death, they have a Touch of Death attack. So, don't try melee, unless you want to be reduced to a red stain on the floor… Well, you can try melee if you're really brave, and proficient. Fire damage dealing weapons, like a Dragon Long Sword, are an effective approach, and will kill them quickly.
They have the annoying habit of summoning and reviving Shadowlurker.
This guy is easy. People farm him for souls. Simply shoot arrows down at him from the tunnel with Graverobber Blige (don't try to lock on, just aim low after the first arrow since he will start moving down the stairs). Note that Patches, the Hyena is in the room beneath/behind the altar here, if you want to rescue Saint Urbain for high level miracles (and who wouldn't want Second Chance from the 4-2 boss?).
The first reaper is very easy to melee. Run accross the upper bridge and kill the 2-3 Shadowlurker that are up there. When you get to the middle part, you can look down and lock onto the reaper. Jump down and roll when you hit the ground, this will hit the reaper for about 2-3 damage stunning him, then you can immediately start attacking him and he gets stunned every time you hit him. The only thing you need to worry about is the 2 Shadowlurker on the bottom, kill the reaper before they attack you or you will loose your momentum.
Also, if you have a bunch of Soul Remains clogging your inventory, or you aren't sure about a direct assault, toss one at one of the two shadowlurker. As soon as you do switch target to the reaper and charge. The remains will cause them all to ignore you and beat up the guy you tossed them at. Easy kill, happy farming.
*second addendum to Alternative strategy
Follow the alternative strategy up until you lock onto the Reaper. Instead of jumping down, use Flame Toss. He will try to fire up at you, but all his attacks will hit the ground beneath you.
Sprint along the left hand walkway and roll as far forward and as far left as you can into the back left corner of the room (behind the Reaper and to his right). You will drop down and land on some vases, but the Reaper won't turn around. Then simply lock on and hit him with Fire Spray for an easy kill. You don't even need the Thief's Ring.
This guy is a bit tougher. This is because he is guarded by respawning Shadowlurkers, including the ones that fire the purple magic beams at you. He is actually right below you when you first enter the room, to the right. Some people drop off here to fight him directly. They tend to die when he merely touches them, or when their melee attacks push him off the cliff behind and they follow him down.
So what to do? Rush the first Shadowlurker and beat him. Walk down to the corner and note where he respawns. Once you beat him here, look to your left, down a bit, at the flat area with the pillars. See those two beady yellow eyes looking at you from between the pillars on the right? That is the Reaper, shoot him with arrows to draw him out into the open. When the Shadowlurker respawns, simply use melee to beat him. They are pushovers against melee. Once killed, beware of the ambushes by the slinky female Shadowlurkers. You'll hear them giggle before they impale you with tentacles.
Alternatively, if you hit the reaper with any melee attack once or twice, he will fall down a pit behind him and die.
Note: It is possible to dodge the beams of the first two Shadowlurkers, though it still is risky. To do this, keep rolling diagonally between the Shadowlurker's body and the wall until its attack is completed. Afterward, you'll be close enough to melee before they attack again.
This guy is tricky as well. Kill the blue melee-only Shadowlurker. Then turn right and note the purple ranged Shadowlurker. In front of this enemy, to your left and out of sight, is the last Reaper. You can either dash forward, block the beam, and attempt to stab the Reaper with a poisoned weapon to kill him slowly(a poisoned spear is the safest option).
Alternatively, just cast a Poison Cloud spell at the purple Shadowlurker and it will catch the Reaper as well. If you can't do that, or don't want to bother, just use arrows on the Shadowlurker and draw the Reaper out then use arrows on him as well. Congrats! No more Reapers. Another safe option here is to just run past these two and down the stairs, and then turn and kill the reaper from below with a few ranged attacks.
Another safe strategy for this reaper is to attack him from the level above (assuming you've killed the second reaper and the female Shadowlurkers). Take out your bow and stand on the path above, near the cliff-side exit but where there's no wall. You may have to move left or right to see him since there's pillars in the way. You should be able to take him down if you do decent damage with bows.
Another strategy for the third is shooting him from the stairs down immediately after the second reaper's first Shadowlurker's spawn point. You'll be shooting through columns, but fortunately the reaper's own shadowlurker will block his path for you.
Note: It would seem that this has been patched in some versions of the game.
If patched, the 3rd reaper won't spawn until you run around the corner, behind which he hides.
He is still fairly easy to kill if you simply kill the two shadowlurkers on the way, run around the corner and see him, and then run back out and up to the next level, from where he's snipe-able.