Despite that there isn't an established order for the whole of the ninja world, the clans that thrive or decline in these dark times do have some level of organization that's been well established for many years. Below are the ranks and a brief description of what the role entails:
Head-of-House; House Head: Typically the patriarch of the clan in question, the Head-of-House, alternatively, House Head, is basically the one running the show and the person who is in immediate control of the affairs of his/her clan. It's this person who holds the highest authority over his clan and who ultimately decides what does and doesn't happen within the clan as well as who and who they don't associate themselves with.
Adviser: The Adviser is more or less the House Head's right-hand man (or woman) that tends to be alongside him/her wherever he/she goes and aids in the greater decision-making process. The Adviser generally has a lot of say in the clan's affairs. This person tends to be recognized as the wisest of his/her clan.
Marshal: Whereas the Adviser is the House Head's right-hand man, the Marshal is his/her left-hand man with equal say in the affairs of the clan. Unlike the Adviser, this person is likely put in charge, on the field, over that clan's trained shinobi during wartime or even on high-ranking assignments given to the clan. The Marshal is normally chosen for his/her bravery and/or sense of principle.
Steward: This person tends to the clan's domestic needs and often oversees their finances. The Steward is usually the one in charge of the clan's servants during large public events. Also clan's don't expect their Steward to go to the field of battle during wartime, instead, to keep things in order at the clan settlement.
Ōshitsu no Tokubetsuna Tasukufōsu (ŌTT): The Ōshitsu no Tokubetsuna Tasukufōsu (ŌTT) also known as the "Royal Special Task Force" is responsible for typically protecting House Heads and their families as well as their dignitaries. The ŌTT is also tasked with the highest-ranking assignments, typically outside of the battlefield and behind the scenes. In order to become a member of the ŌTT it's required that you're applying as at least a Jōnin ranked Ninja and you need to be particularly skillful.
Jōnin: These are a clan's most highly skilled shinobi who have undergone plenty of assignments and have a lot of field experience. In order to become a Jōnin you need to have had a lot experience as a Chūnin and be able to use higher-ranked jutsu. Being a Jōnin gives you authority over both Chūnin and Genin, the latter of which Jōnin typically teach in cells to hone their teamwork and cooperation with other ninja, since most ninja at the time are deployed onto the field of battle.
Chūnin: These are average-level shinobi who have proven themselves capable of all the basics and have some experience on the field. Given their knowledge of ninjutsu and the ninja world they are typically assigned as instructors for younger clansmen or viewed upon as more well-trained and disciplined than their Genin subordinates when on the battlefield. Chūnin typically take orders from Jōnin on the field, but have taken on more senior roles, though, it's dependent on their experience and level of skill.
Genin: These are your youngest and typically most energetic members of the clan. They are taught to operate as a team while maintaining that team's security as a unit. They are not so young that they're still being educated on the basics, it's just they typically have very little experience with battle. Despite their young age they too are deployed onto the battlefield during wartime alongside Chūnin and Jōnin. Until then, their skills are honed by completing assignments under the tutelage of either a Chūnin or Jōnin, though members of the "main" family tend to go on assignments together.