#also this is fine bc I can reuse it for Cintamani along the line

[tcfactory]

Random In Tune worldbuilding tidbid that won't come up for a while but I've been thinking about it today:

There are only two people on the sect who can safely dual cultivate with MQF when his core is not shielded/filtered: WQW, who spent the last twenty years developing an immunity (because they were so late with his treatment, the toxins couldn't be removed from his body so the only way to fix his leg was to render him completely immune and then repair the damage) and YQY, because YQY's spirit veins are so fucked up that the toxic qi just runs through him with minimal absorption that can be mitigated with a pill.

Xuan Su destroyed almost all of YQY's spiritual system when he picked it up too early. His spirit veins were obliterated except for a few vestiges around his core (which formed as a defensive measure against the onslaught of the sword's qi and holds not just his qi but basically the entirety of his life force as well) and the parts in his sword arm that were already developed enough to handle the deluge of power.

He was confined to the caves because without the saturation of spiritual energy his body would have just shut down because he had no spiritual veins to supply his body with qi. Breaking his bones and ligaments was part of the process of building him an artificial meridian system (that's why his spirit veins are "straight like someone drew them with a ruler" because that's exactly what happened), but it's not really effective.

They have abysmally low efficiency when it comes to qi absorption; he has to circulate most of his insanely huge pool of qi through them constantly to get a normal amount of energy to the rest of his body. If his spiritual veins are like irrigation channels in a field, then the artificial veins have concrete walls and the only water escaping them is what spills out the top and seeps through the cracks.

If he cuts out his core and the veins in his arm from direct circulation (a quirk he never really thought about, but MQF was clawing at the walls when he heard he can do that because wtf ) then he can run someone's qi through his body and back to them with basically no impact on him.

And if he wants to take on harmful qi anyway then he can just dilute it in his own energy because it would be a drop in the fucking ocean. The size of his qi reserves are more in line with someone late in nascent soul level, usually at the stage where people ascend to the heavens, he just can't utilize it.

(Except when he's a dumbass who wants to take the qi of his beloved SQQ into his core and gets hit with the 'suddenly a teenager again' stick for his troubles. This dumbass.)