Conspiracy
Soraka had not taken part in Karya's plan, though she had indeed offered Karya considerable help.
Karya, for her part, had not overstayed her welcome. After sipping a cup of tea, she said goodbye to Soraka and headed down the mountain to Nareumajel with Zoe.
Then, when Karya asked Zoe how she had prepared, she got the answer she had expected: "I haven't prepared at all."
After spending too long in the celestial realm, Zoe had developed the common affliction of long-lived beings: she had a poor grasp of time and found it hard to seize opportunities. Take the present, for instance. Even though she had been back in Runeterra for three and a half years, she still seemed as if she had only just returned. Everything here fascinated her, whether it was revisiting familiar places or discovering something new.
Even the Aspects had already begun to make their move, yet she remained blissfully unaware.
From that perspective, Sol choosing her as an ally in his revenge was rather unreliable.
Of course, that sort of unreliability was perfectly normal. If Zoe herself hadn't been so guileless, Twilight wouldn't have chosen her as its Aspect.
As it happened, it was precisely because she was "unreliable" that the Aspects didn't consider her a threat.
From their perspective, Zoe was someone who caused trouble if provoked, but caused no trouble if left alone. She posed a bit of a risk, but not much, so they had decided to let her be.
Unfortunately, they clearly didn't know that Zoe had been in contact with Karya for a long time. If they had, they would probably have acted already. Without sending an Aspect to deal with her personally, they might not have been able to do anything to Zoe, but they could at least