for the greater good...
sometime around 1000 the archangel raziel is summoned by a warlock on earth in order to help with an intense demonic threat. in exchange for loyalty to fight and keep the peace between the downworld and human world, the angel grants the warlock his blood in a cup. the men that drink then find themselves empowered by the angel blood that permanently changes them. their children are then of both human and angel blood, and the shadowhunters are born. through specific angelic runes, the shadowhunters gain their extended powers.
the clave is the name for the political body that makes up all active shadowhunters. they enforce 'the law' among the shadowhunters and the downworld, with the aim to keep its presence a secret from the human/mundane world. the accords, signed by different groups (like the seelie court, werewolf packs, vampires, warlocks, etc alongside the shadowhunters) swear to adhere to these laws. as of 2023, a selection of 'downworld deputies' were selected- members of each group within new york city, to represent and serve on a kind of 'court' alongside the shadowhunters of the new york city institute. regular meetings are held to upkeep relations between the clave and the downworld and for either side to raise any issues and proposals.
while shadowhunters are naturally aligned with the angels due to the connection in their blood, there have been a lot of tensions in the past year. some older members of the clave don't like the way the clave has moved into more of a clear alliance with the downworld. some still see them as enemies and would prefer to be more clearly aligned with heaven. those in charge (like jia and alec) naturally don't support this and stand by their choices to keep things open and positive with the downworld. it is set to cause continued tension as things grow within all the different factions.