>>96395499
The chain represents that chaining of the past. Blackshields scour their chapter iconography from their pauldron and wrap it in chains to show they are dedicate to the deathwatch and no longer part of their chapter. Its kind of a mark of shame, like their home chapter wont let them use the iconography anymore. Titus was a blackshield, and he had the chained up scoured pauldron when he was in the Deathwatch. He keeps the chained fist when returns to the Ultramarines as a symbol of his service in the Deathwatch, a tradition that was brought to the DW from the Black Templars.