The Shapeshifter bloodline.
Daneel had only said that he would be taking the Path of the Cockroach in front of his Sovereigns as he had wanted to see their reactions. Of course, in reality, his plan had been to choose this and find some way to overcome its weaknesses so that he could use the powers of the Cockroach, and the only other reason he hadn't spelled that out was that although he was confident that he could accomplish it, he hadn't wanted to talk about it until he did so.
Ever since Daneel had heard about it, it had completely captivated his entire mind, and it had even shaped the whole image he had regarding what a 'perfect' Bloodline was. In fact, unconsciously, he had even begun to think that this was the peak that no one could even dream of – to be able to mimic any bloodline that one wished, instead of being restricted to one, which would lead to one having some or the other drawback.
