BTW, a recap on how, once a wizard has somehow fled (or even has been killed by the Sorcerer, since the Meteor Strike doesn't prevent the Wizard's Clone to activate...) can use of no less than TEN ways to locate someone you don't know based on a rough description like "the guy that killed my friend or me", in a world where the DM doesn't take any action besides what is provided by the rules [and yes, that's the strange one where nobody is ever surprised].
1. Commune.
By RAW, you can ask three questions and must receive a correct answer on all case. There is a paragraphe stating that deities aren't necessarily omniscient so the DM can always veto some information, but that's DM fiat to block the spell, not to provide the RAW-abiding correct answer. Questions can only be answered by yes or no. Anyone who played "Who is it?" can imagine how to draw a composite face of the culprit in a few questions, and identifying his name takes a few tries (Is the name starting with A?...) Drawback: it takes a long time since you can reliably cast it only once per long rest.
2. Contingency
Contigent Sending triggered on "Whenever I hold a golden rod right toward the person who killed my friend". I know, it's a contrived trigger, but by RAW there is no limit on the trigger. Magic happens. Two casting separated by a Teleport and you can get a rather precise reading on the location of the culprit.
3. Glyph of Warding
Triggers are more limited. Choose a visual spell light that can target an area in a spell glyph, triggered by proximity of the guy you seek, of which there is no limit. Nothing defeat the Rod of Dichotomy ^2. Drawback : can take a few days.
4. Scrying
You only need to have heard of the target. Best case: it works. But even if it fails, you gather information. If the target is protected from appearing to magical sensors, you can see their surroundings. That's enough to attempt a teleport. Of course you risk failing, so prepare to take a few days to work. If the spell simply fails but you can recast it the next round, you gained information that the target is under a spell protecting him from being targetted (if it was a succesful saving throw, the spell couldn't be cast for 24h). Try later. Drawback: Team Sorceror could be all under permanent Nondetection. Deduce that he's burning 80 kgp a year on diamond dust. Use Investigation skills to identify such a large scale buyer's business associates. Scry them.
5. Legend Lore
Given the effort of the Sorcerer not to be identified, it could be argued that he isn't of legendary importance. In a "Sorcerer King" scenario, however, where he has already subverted many cities by impersonating wizards doing bad things and then saving key, gullible, people in the last minute and repairing the material damage to become a hero, he would be of legendary importance and would be exposed to information gathering this way. As in "Who is the guy who used immense magic to save King So-and-So?" Drawback: doesn't work in a fledgling ennemy starting his career and who never did something talesworthy. On the other hand, it should work on the level 20 Assassin, since level 20 are planar heroes. You might always get some intersting tidbit, like the place he was last seen.
6. Visions of the Past
Can get visual and emotional informations on the target without targetting it. Good to use on an item like "a corpse", when investigating a series of suspicious wizard murders. Drawback: you need some forensic talent to gather the relevant item, like the poison used by the assassin, a pinch of lime a bunch of out-of-season snow or a catterpillar cocoon.
7. Resurrection
Unless the Sorcerer achieves consistant killing without being seen by its victim, and that means 100% of the time, not even "nearly always" will do, there will be a victim who will have seen him. Resurrect the deceased Wizard and interrogate him. If he isn't cooperative, kill him again and Speak with his skull. Getting information will make the other information gathering venues easier to open.
8. Divination
With the DM having lost any adjudication power, he must provide a truthful answer to an activity to occur in the next seven days. It's limited to an "event, goal or activity", which is pretty narrow. "Will my walk directly east over the next hour make me closer to my the assassin who killed by friend?" is therefore a perfectly valid question. Triangulate as needed.
9. Summon or be an Invisible Stalker.
Given the shortage of CR 6 air elemental, the DM has no other choice of providing an invisible stalker for a summon. One hour is largely enough to get the information you need, provided you speak Auran. Actually a few rounds of chatting are enough. If the DM cheats by using DM fiat to deny Invisible Stalker, which would be against the rules set up for this contest but has nonetheless been claimed to be the case by SOME participants in the thread, just cast True Polymorph on your pet rock.
10. Summon an Orthon
Upcast Summon Greater Daemon to level 9. You can specify a demon type, choose "Orthon". Do whatever is needed to take control of it. If needed, make a Simulacrum of one. Send him to the place the Sorcerer is, located by one of the aforementionned means, like an Invisible Stalker. Just ask him to do one attack and leave. Bonus: works across planes if the Sorcerer decides to Planeshift away if your alpha strike happens to fail.
