Level: 45+.
1. Head to Katta Castellum and find Saumeem Unja (loc 150, -2000) left up the stairs second door on the right. Hail him and say 'what assassins?'.

2. Saumeem Unja tells you to kill FOUR assassins and deliver their Coterie Assassin Garrotes to him.
3. One of the assassins spawns in the triangular area (loc 300, -1500) along the longest wall and has a four hour spawn time (two other assassins spawn down the slope behind the buildings). Coterie Assassins are invisible so you need to trigger him by walking by or have see invis on and it might be superstitious but DON'T sit along the long wall, sit in the corner of the room (spent 25 hours on and off along the wall and nothing spawned. Was standing away from the wall in a fight with a guard and he jumped me from behind.. assassin style).
NOTE: To save time you will want to look out for Sasha (shows up on sense undead) and kill her for a part later on (see step 6). Also if you are mid 40s you can hunt the the graveyard and if you are mid 50s+ you can hunt the evil guards outside Nathyn Illuminous' House to pass the time.

4. Hand in four Garrotes to Saumeem Unja to receive the Reflective Combine Claymore.
5. Say 'what coterie infiltrators' and Saumeem Unja will tell you he needs two vampyre infiltrator fangs, which drop from a vampyre named Sasha Aliquin and a gem of condensed flame, which drops from the Sun Reverent King in the Scarlet Desert.

Sasha right before she despawns
6. Sasha Aliquin is a strange mob and can be found walking down the stairs into the 'Nectar of Unity' tavern (-250, -1000) when she spawns. She spawns roughly every two hours. She is an undead enchanter that can flurry of blows and is a close fight for a 58 Paladin. Make sure you have all your AC, HP, Magic and Touch of Nife buffs on, load at least three stuns and a heal. When you first engage her root her or she will just mezmerize you, keep walking into the tavern and despawn. During the fight everytime you see her casting, stun her. Towards the end of the fight chain stun her or she will gate up the stairs and heal slightly. You will need LoH.

6. The Sun Reverent King is located in the Scarlet Desert (through the tunnels over the sea). He spawns on a plateau that contains many Sun Reverents. Kill everything in the ruins and the Sun Reverent King will eventually spawn (sometimes he spawns where the Sun Priest spawns). All including the Sun Reverent King can be soloed by a 58+ Paladin with around 40 mana.
6. Turn them in and your Reflective Combine Claymore to receive the Holy Sword Ashbringer: