There are multiple channels that your character may have heard of the Clan.
Meeting Clan Members/Leaders - This will need to be arranged OOC, unless characters just happen to meet organically in the world already. Do not assume the leaders or other Clan members will have met your character or know who they are if we've never roleplayed before. Our characters will - rightfully - be confused and not know who you are or where you came from.
Flyers / Posters - They may have seen some recruiting flyers or posters in regions the Clan is currently working out of at the time of your joining. Typically these will include information asking for mercenaries or adventurers who are looking for a group to join that they plan to stay in for a long time and don't have conflicting duties / interests of other factions or alliances that would interfere with Clan attendance as much as possible.
Approached by a Stranger of no name - Its possible that your character may have met a liaison of the Clan, perhaps in a tavern or back alleyway or an outlaws refuge. This stranger would be a Bosmer dressed in black, with almost-bald peach fuzz hair, who claims to have no name that needs speaking. He would mention a job opportunity with the Clan, and to seek them out at the Nocturnal Temple in Markarth, just off to the side of Understone Keep.
Rumors in the Underground - The Clan does do "underground" work as well as "upstanding" work. Thievery, assassination, smuggling, courier work, and more. In particular, the Clan would be known to those within circles who ally themselves closely to Nocturnal, such as within the Thieves Guild or Nocturnal cults. Some rare few may even have heard a rumor or two that the Clan has or is led by a Daedric Champion to Nocturnal, if they are really well-connected or work very close to Daedric Princes (most notably: Nocturnal, Hircine, and Dagon).
Northern Elsweyr / Dragonguard - Around mid 2E 587, the Clan did a large portion of work in Elsweyr chasing the rumors of dragons and necromancers. For the most part, the Clan focused on the rural countrysides, defending civilians from dragon attacks, often for little or no pay. Their reputation in the region grew quickly and with great positivity. The Clan left the region for other ventures after the re-founding of the Dragonguard began, leaving southern Elsweyr to them.
Rivenspire - The Clan worked hard for a time in the region of Rivenspire, circa early 2E 587 to mid 2E 588, under the rulers of Shornhelm as well as, to some small degree, High King Emeric's court. The Clan worked in the region dealing with vampire and bloodfiend attacks, goblins, wolves, pirates, and bandits all across the region, as well as running intelligence and letters for the Covenant between the warfront and Wayrest. They set up their main headquarters in Fell's Run for a time, arranging an agreement with Shornhelm and the mayor of Fell's Run to use the town as they saw fit in exchange for offering protective services as a guard/militia force, keeping the town's borders and surrounding countryside safe. The Clan officially moved from the region mid 2E 588 and re-established their HQ in Solitude, Western Skyrim, leaving it in the hands of the Silvars.
Skyrim / The Reach - Arguably where the Clan's reputation runs the highest. The Clan moved to Solitude in mid 2E 588 chasing rumors of the Harrowstorms and vampires ravaging the north, since many of the Clan were from Skyrim and the Reach and saw it as a personal matter. The Clan played a critical role in fighting the Harrowstorms and the Gray Host, in both Western Skyrim and the Reach, earning favor both with the new Jarl of Solitude and the Ard of Markarth, though not without some heavy costs among the Clan's ranks. The Clan also became key players in a war brought to Wrothgar, the Reach, and Skyrim by an Orc Malacath cult known as "Nozarga" not long after the Gray Host fell - a war that was uniquely fought with Orc, Nord, and Reach allies working together. It was due to this that the Clan ended up working under the service of both Solitude and Markarth, officially regarded as agents of the Ard in particular, with an interest in helping maintain the rare peace currently established between East and West Skyrim and the Reach. They moved their HQ from Solitude to Leyawiin when they departed for Blackwood.
Markarth Temple to Nocturnal - Following victories against both the Gray Host and the Nozarga, Ard Caddach granted the Clan a place in the city to set up permanent residence. Finding the place too large for the Clan's needs and too disconnected from most of the rest of Tamriel, Alekt decided to turn it into a semi-public Temple to Nocturnal, welcome to all who work in the shadows including thieves, assassins, smugglers, and more - both as a place to worship, and to meet other like-minded individuals and coordinate jobs with them.
Blackwood - While they have some reputation in Blackwood around mid 2E 589, its mostly small regarding their activity in the region. Most of their work in Blackwood is spoken of among soldiers or a couple of the elite regarding their combating the Waking Flame, while among civilians, any major reputation is mostly spill-over from the bordering Elsweyr region due to their time fighting dragons years earlier. The majority of the Clan moved out of Blackwood nearing winter to return north to Skyrim and the Reach.
Meeting Clan Members/Leaders - This will need to be arranged OOC, unless characters just happen to meet organically in the world already. Do not assume the leaders or other Clan members will have met your character or know who they are if we've never roleplayed before. Our characters will - rightfully - be confused and not know who you are or where you came from.
Flyers / Posters - They may have seen some recruiting flyers or posters in regions the Clan is currently working out of at the time of your joining. Typically these will include information asking for mercenaries or adventurers who are looking for a group to join that they plan to stay in for a long time and don't have conflicting duties / interests of other factions or alliances that would interfere with Clan attendance as much as possible.
Approached by a Stranger of no name - Its possible that your character may have met a liaison of the Clan, perhaps in a tavern or back alleyway or an outlaws refuge. This stranger would be a Bosmer dressed in black, with almost-bald peach fuzz hair, who claims to have no name that needs speaking. He would mention a job opportunity with the Clan, and to seek them out at the Nocturnal Temple in Markarth, just off to the side of Understone Keep.
Rumors in the Underground - The Clan does do "underground" work as well as "upstanding" work. Thievery, assassination, smuggling, courier work, and more. In particular, the Clan would be known to those within circles who ally themselves closely to Nocturnal, such as within the Thieves Guild or Nocturnal cults. Some rare few may even have heard a rumor or two that the Clan has or is led by a Daedric Champion to Nocturnal, if they are really well-connected or work very close to Daedric Princes (most notably: Nocturnal, Hircine, and Dagon).
Northern Elsweyr / Dragonguard - Around mid 2E 587, the Clan did a large portion of work in Elsweyr chasing the rumors of dragons and necromancers. For the most part, the Clan focused on the rural countrysides, defending civilians from dragon attacks, often for little or no pay. Their reputation in the region grew quickly and with great positivity. The Clan left the region for other ventures after the re-founding of the Dragonguard began, leaving southern Elsweyr to them.
Rivenspire - The Clan worked hard for a time in the region of Rivenspire, circa early 2E 587 to mid 2E 588, under the rulers of Shornhelm as well as, to some small degree, High King Emeric's court. The Clan worked in the region dealing with vampire and bloodfiend attacks, goblins, wolves, pirates, and bandits all across the region, as well as running intelligence and letters for the Covenant between the warfront and Wayrest. They set up their main headquarters in Fell's Run for a time, arranging an agreement with Shornhelm and the mayor of Fell's Run to use the town as they saw fit in exchange for offering protective services as a guard/militia force, keeping the town's borders and surrounding countryside safe. The Clan officially moved from the region mid 2E 588 and re-established their HQ in Solitude, Western Skyrim, leaving it in the hands of the Silvars.
Skyrim / The Reach - Arguably where the Clan's reputation runs the highest. The Clan moved to Solitude in mid 2E 588 chasing rumors of the Harrowstorms and vampires ravaging the north, since many of the Clan were from Skyrim and the Reach and saw it as a personal matter. The Clan played a critical role in fighting the Harrowstorms and the Gray Host, in both Western Skyrim and the Reach, earning favor both with the new Jarl of Solitude and the Ard of Markarth, though not without some heavy costs among the Clan's ranks. The Clan also became key players in a war brought to Wrothgar, the Reach, and Skyrim by an Orc Malacath cult known as "Nozarga" not long after the Gray Host fell - a war that was uniquely fought with Orc, Nord, and Reach allies working together. It was due to this that the Clan ended up working under the service of both Solitude and Markarth, officially regarded as agents of the Ard in particular, with an interest in helping maintain the rare peace currently established between East and West Skyrim and the Reach. They moved their HQ from Solitude to Leyawiin when they departed for Blackwood.
Markarth Temple to Nocturnal - Following victories against both the Gray Host and the Nozarga, Ard Caddach granted the Clan a place in the city to set up permanent residence. Finding the place too large for the Clan's needs and too disconnected from most of the rest of Tamriel, Alekt decided to turn it into a semi-public Temple to Nocturnal, welcome to all who work in the shadows including thieves, assassins, smugglers, and more - both as a place to worship, and to meet other like-minded individuals and coordinate jobs with them.
Blackwood - While they have some reputation in Blackwood around mid 2E 589, its mostly small regarding their activity in the region. Most of their work in Blackwood is spoken of among soldiers or a couple of the elite regarding their combating the Waking Flame, while among civilians, any major reputation is mostly spill-over from the bordering Elsweyr region due to their time fighting dragons years earlier. The majority of the Clan moved out of Blackwood nearing winter to return north to Skyrim and the Reach.