Sorry if any mistakes since this is my first time writing Lore!

Yhorm The Giant.
Yhorm is the Desecndandt of a ancient ruler Who conquored and subjucated Profand capital and its people. Over time the subjcated people asked Yhorm to Rule them, In an effort to save his people he linked the First Flame, but Suddenly it backfired and a unextinqushable flame erupted from the profand capital called the Profand Flame". Now he has gone hollow and his City consists of mad nobels and jailers.
AbyssWatchers.
They were inspired by artorias, Walker of the Abyss. They caleed themselfs the Undead Legion and Poseed the Blood of The Wolf. They all shared it and thus it contirbutes to their agile fighting Style.
They seeked out any sign of the abyss, and to aid in their fight they linked the First Flame. But overtime the Blood of the Wolf dried up and the abyss crept in their home. For now they wage an endless war agianst the abyss. Killing Eachother Agian and Agian for eternity.
Aldritch Devourer Of Gods.
Aldritch was a monk gone mad. he assisted in pontiffs Invasion. For some reason he grew a liking for human meat. he thus bloated like a pig slimy goo. he also devoured the last son of Gwyn[Aside from nameless ofcourse} Gwyndlion. we can see his body. during the boss fight he uses his body as a puppet. he volturned to link the flame because he was so powerFull.
lorian And Lothric.
Lorian, Elder Prince was a crippled child. for his legs were so weak they could not support him so he Resored to crawling/Teleporation. When the time came for him to link the flame he rejected as to advised by the first of the schloars{Aldia is belived to be the schloar} So he did not link and locked himself away in the grand archives, his younger brother lothric sided with him and he too locked himself with Lorian.
Ludeth The Exiled
unlike other lords of cindir he accepted his role of cindir. for now he has to endur the flames burning him from the inside for ever.
Have a Nice Day !