When you purchase the tower key from the handmaiden in Firelink Shrine for 20,000 souls, you can enter the bell tower next to the shrine only to be locked in by a certain Patches the 'Unbreakable'. This character has actually appeared in all of the 'Souls' games as well as Bloodborne. His bald head and suspicious attitude has made him one of the more memorable characters in 'Soulsborne'. He was Patches the 'Hyena' in Demon's Souls, 'Trusty' Patches in Dark Souls and the 'Spider' in Bloodborne. He did not appear in Dark Souls 2, however there are fan theories that say that a certain 'Mild-Mannered' Pate is another version of Patches, mainly because of their shared habit of ensnaring players in lethal situations with the intent of looting their bodies post-mortem.
The covenant Watchdogs of Farron resemble the bond that was shown between Knight Artorias and his wolf Sif. The covenant's lord is a giant black wolf, the Lords of Cinder that fall under this covenant are called the Abyss Watchers. They seem to have the same fighting style as Artorias and look somewhat similar so possibly former brothers in arms of the iconic Artorias "The Abyss Walker".