Lith didn't want Protector to leave, but he didn't have much of a choice. What Faluel said was true, plus she was willing to explain to him the secret behind his seven eyes, no strings attached.
Or at least so she said.
Even if she were to refuse to teach him about runes, even if she placed unacceptable conditions for his apprenticeship, between what he had learned about Origin Flames and what he was about to learn, it was more than he could have ever asked.
'I don't like this, but since Solus will leave together with Protector, our secret is safe. Moreover, if things go south, I can always use our mind link to ask them both for help.' He thought.
After Protector left, Lith also cut off his mind link with Solus, in the case that the Hydra had some way to notice it. Both Scarlett and Gaaron had somehow established a mind link with him.