Bungie introduced a new race and a rather peculiar character during the Vow of the Disciple raid in Destiny 2, leaving many with questions about its past.
Vow of the Disciple was well-received by Destiny 2 players in general as they praised the mechanics and dynamics of the raid. People also found it odd that they didn't recognize the final boss or didn't even know what he is.
Rhulk, Disciple of the Witness, left the players in awe due to his unique appearance and mannerisms throughout the fight. It's this uniqueness that players found weird as Rhulk was never seen before and neither were any members of his race. The mystery was quickly solved through several lore entries and audio logs and here is a rundown of what the lore hounds found so far.
Warning - spoilers ahead.
Lubrae is a distant planet that the players were never introduced to and this is where Rhulk hails from. As such, his race is known as Lubraeans and this particular Disciple is the first and the last of the race we will get to witness.
His planet was visited by the Traveler, ushering an age of prosperity, just like on Earth. In a similar fashion, several factions formed but in Lubrae's case, there was one dominant, prosperous faction and then there were clans that existed outside of it. Rhulk was a member of one such clan.
The dominant faction pretty much oppressed the clans and at one point, Rhulk's father was taken by their soldiers. He swore revenge on them and started chasing the aggressors in an attempt to kill them and liberate his father. By the time the son met the father, the latter had become an upstanding citizen in the prosperous city and the revelation started Rhulk's descent into madness.
He joined the army of the prosperous faction, exhibited exceptional aggression and eventually stumbled upon the Witness in the depths of Lubrae. Having had enough of the madness around him, Rhulk only found some semblance of normalcy with the being he met, the same being who gave him immense power at the same time.
Upon returning to the city, Rhulk murdered literally everyone but his rampage didn't stop there. He then used the technology of Lubraeans to destroy one of the planet's suns, eventually shutting down all life on it.
Having driven his race extinct, Rhulk is the first and last Lubraean we meet in Destiny 2.
After those events, Rhulk stuck with the Witness and on its orders went to assist Savathun with spawning more Hive worms. When she chose the Light instead, Savathun imprisoned the Disciple in the pyramid ship, which is why we find him and the ship in the Throne World.
One interesting detail is that the army of the prosperous faction in Rhulk's history used glaives and Rhulk himself used one when he went on his crusade against everything he knew, the same one we get to obtain - Lubrae's Ruin.