u/Mr_ksngrid

From what it seems, Ryoshu raised sinclair. In his uptie story, he mentions his master being sickly or fragile, which could refer to her current state of entanglement (which is described in canto 9 as being under constant suffering for araya, and HoS ryoshu talks about being unable to sleep peacefully) or her fragile self before entering entanglement as she was kept in the time vault for days on end without any sort of sustenance or stimulation.

My guess is that she was assigned sinclair as a leash in the same way araya did for lcb ryoshu, to make sure she wouldn’t try to escape the house of spiders and their entanglement experiments.
- Her having a similar relationship with sinclair explains why she targets him last with the tiansha star effect, which mirrors how araya was the last sacrifice to muga ryoshu (or the one death that started her descent into muga).
- Her special lines with ren in canto 9 and md talk about how she seems to have never met a ren in her world, even though she recognises the other apprentices.
- Alongside how she mentions that ren feels familiar, even though their threads have “never been entangled”, it seems like sinclair got araya’d from her memory in a way the others did not.
- Sinclair’s s2 “nameless slash” reuse mechanic isn’t anywhere in ren’s kit. Instead, it seems to be emulated from araya’s “formless cut”.
- Sinclair also has bleed in his kit, whereas ren is a pure poise unit. Araya is also a pure poise unit, but tiansha star ryoshu is a poise-bleed unit. Considering her general inclination towards blood, i wouldn’t be surprised if ryoshu developed a sword style that leans towards bleed, which sinclair emulated, with ryoshu’s burn coming from arayashiki.
- sinclair seems to be aware that he will never become a true pinky member. He doesn’t have the “training to inherit the name of a star” passive that ren does, and he acknowledges that he’s going to die soon in his uptie story: “My life will soon come to an end. What is the point of dreaming this fleeting dream?”
- Ryoshu mentions a specific unnamed memory that seemed to be holding her back from murdering everyone in her uptie story: “And of course, even that memory I abominated, and there was nothing to stay my sword hand.”

However, the most interesting detail to me is that sinclair’s voice lines reference ryoshu as a previous apprentice before the 5 in such a way that he doesn’t seem to know that ryoshu is the current dihui star. I’m inclined to believe that ryoshu uses the veil/shiomi form when teaching sinclair the same way araya did for ren, but it means that there was a time period after Ryoshu became an adult and started taking on tasks for the house but before the other apprentices were taken in? Ryoshu also only talks about 4 threads when discussing the house of spiders, which means that there is no pinky thread for her. This could mean that she never had a shiomi or that shiomi was dealt with early on.

So from what i’ve gathered so far, the timeline seems to go like so:

1. House of spiders is made, ryoshu is born (and shiomi likely gotten rid of somehow)
2. Ryoshu gets entangled and starts carrying out tasks for the house
3. The apprentices are taken in, Ryoshu gets sinclair
4. Ryoshu raises Sinclair on her own style but grows weaker over time, likely due to the entanglement
5. Something happens. Most likely sinclair dies.
6. Without sinclair holding her back, she rampages the house of spiders. The first memories to be eaten by the rampage are her memories of sinclair. She then becomes the concept incinerator.

The main missing pieces are why the apprentices are taken in (aside from sinclair who’s meant to be a leash), and what actually happened on 6 to cause her to rampage now. Since she’s described to have waning health in sinclair’s uptie story, maybe she just failed to hold back the muga and sinclair become her first victim? Maybe her imperfect training leads him to die on one of the missions that he took in lieu of her? Maybe the NFs just straight up killed him? Who knows.

My guess for now is that ryoshu started weakening from the entanglement first, which left her unable to carry out all the house’s tasks. The nursefathers then brought in their apprentices to help pick up the slack, with sinclair carrying out the ryoshu jobs and looking after her in return for training. During her most fragile moment, she likely learns about sinclair’s death and goes on a rampage seperate from her killing the nursefathers, during which she cuts away all her memories of sinclair. Finally, left with nothing but the main of her entanglement and nothing left in the house to bring her joy, she kills the nursefathers and becomes muga.