Murmur

Shrouded composed almost entirely of fine, thread-like shadow tentacles, typically taking the form of two connected, emaciated-looking humanoids whose torsos dissolve into tentacles. Originally twin siblings, functionally acting as one after spending centuries together. Two sets of eyes and light colorings- blue and orange.
They spend a lot of their time within the seas bordering Krakenmount, having grown bored of administration and exhausted most research opportunities. It's also quite likely that they're spending a lot of time further west, on that island past the Drowned Isles. Nobody knows why, though.
When traveling, they typically take the form of an extremely tall person, masked and cloaked.
Tend to refer to themselves with what appears to be the royal we, although it actually stems from the fact that they are 'two' people. Similarly, their voice sounds like two are speaking at once.
Cotd in general rarely venture far into the sea- the idea of being stranded in a vast stretch of water doesn't really appeal to them. Those that do often pray to Murmur, who in fact responds with some frequency.
Murmur's voice is famously unsettling. It's ordinarily two overlaid voices speaking in unison. However, sometimes one voice says one word and the other another mid-sentence. "Hello there [stranger/intruder]", "Please [leave/die]" etc.

Origins

While their Shrouded ascension resulted in being physically fused together, Murmur wasn't always so continuous a single entity.
Murmur's total 'mass' of threads is less than two whole people, but more than one- around one and a half. In the early days, they'd often share this pool, both appearing as adolescents to compensate. At other times, one could keep a facsimile of their old form, while the other could be a small child. While proximity wasn't strictly required, lacking it caused significant amounts of discomfort for both of them.
They have something of a sympathetic link even when apart, though this is of their own working- not some natural gift resulting from their nature. A lot of what Murmur has is like this- outsiders take for granted that it's fitting that they can do it, but in reality, they had to build the functionality from the ground up- fundamentally, they're just two transhumanist Cotd, not born with anything more than their peers (other than being creepy enough to drive a Kraken to suicide, apparently).
Even centuries into their reign, Murmur regularly split into two for any sort of work where two smaller bodies and different perspectives may be useful- fine labwork, moving furniture etc. Actually acting as two fully independent entities outside of each others' hearing distance, however, was much rarer.