The Elder Scrolls IV: Oblivion Guide - Dark Brotherhood
13: Next of Kin
Retrieve the dead drop orders from the marked bag beneath the tree across from the Fighters and Mages Guild halls in Chorrol. The members of the Draconis family are your next targets. Perennia Draconis, Matthias Draconis, Andreas Draconis, Sibylla Draconis and Caelia Draconis—all of them must be killed.
An arrow pointing to the matron, Perennia Draconis, will appear on your map and compass. Perennia can be found on Applewatch farm, which is just west of Bruma. Follow the area to locate Perennia. Speak to her, and she will mistake you for a member of the Cyrodiil parcel courier service. She'll give you a list of each Draconis family members' whereabouts. Even if you kill her outright, you can still remove the gift list from her corpse afterwards. Start by killing Perennia if you haven't already, and then inspect the gift list. Try to kill her quickly, as she will mostly likely to run when her health gets low.
Look for Perennia Draconis on Applewatch farm and kill her, you monster.
According to the list, Matthias Draconis can be found in the Imperial City's Talos Plaza District, Andreas Draconis in the Drunken Dragon Inn, Sibylla Draconis in Muck Valley Cavern, and Caelia Draconis in Castle Leyawiin.
You can kill the remaining Draconis in any order you wish, but for the sake of using this walkthrough, just follow along. Start by traveling to the Imperial City Talos Plaza District; Mattias can likely be found patrolling the streets. You won't want to attack him in public, as by doing so, you are likely to be confronted by the city's guards. Mattias will head home at around midnight, so locate his house in the Talos Plaza District at around this time. While standing outside his door, enter Sneak Mode and be certain that the eye icon is not bright and solid before picking the lock. Go up the steps to your right upon entering to reach Mattias' Private Quarters. There's someone else in the house, so try your best to sneak past this person as you make your way up the steps and into Mattias' room. Mattias should not be wearing his armour while sleeping, so sneak up and hit him for a damage bonus.
Andreas Draconis is the innkeeper at the Drunken Dragon Inn, which is located along the east road to Leyawiin. Enter the inn, approach the counter, and inform Andreas that his mother bled like a pig; doing so will cause him to recklessly attack you. There should be an Imperial Legion Soldier in the Drunken Dragon Inn who will attempt to protect you the moment Andreas attacks. Just run around the counter to keep your distance from Andreas and allow the Imperial Legion Soldier to strike him down.
Provoke Andreas Draconis into attacking you, and the Imperial Legion Soldier will kill him.
Sibylla Draconis can be found in the Muck Valley Cavern, which is located east of the Imperial City. Enter the cavern to find Sibylla inside. Sibylla will likely attack as soon as she spots you; since there are no witnesses, go at her with all of your might. There may be some woodland creatures in the cave as well, so be careful.
Caelia Draconis can be found in Castle Leyawiin. You may have to kill her in public view, so be sure that to head to your house (if you have one) or another location to drop off any stolen goods that you don't want to lose. If you are caught, you'll then have to pay a 1000 gold fine to avoid being put in jail. The only time Caelia Draconis is really away from the castle is around 8:00AM; at this time she, can be found in the Three Sisters' Inn. While she is in the Three Sisters' Inn is the best chance you have of killing Caelia without incurring a fine. Enter the inn at around 8:00AM and follow the arrow on your compass to the 2nd Floor West hallway. You may be able to sneak up on her while she is seated in the chair, otherwise you'll likely have to settle for a charged power attack, preferably with some sort of poison on the tip of your weapon/arrow.
Look for Caelia Draconis in the Second Floor West hallway of the Three Sister's Inn in Leyawiin at around 8:00AM.
When the last Draconis family member has been killed, your reward, as well as the next dead drop orders, can be found inside of the Stone Well in the Castle Skingrad Courtyard.