User blog comment:Theory of everything/Grimm Speculations Part Six: The Grimm Family Tree/@comment-206.211.150.253-20120905031323

As far as Renard being Nick's father, Renard isn't old enough to be his father (unless Kelly is into underage boys and had an affair with him when he was about 10). We saw Renard's primary focus is power, we saw this when he had possession of the coins. I think it's also about respect since he surely has some issues with this given his history as an outcast with the Royals due to his illegitimacy. It can only help Renard in the future to have Nick on his side and I suspect he chose Nick (over other Grimms) because Nick would be the easiest Grimm to manipulate due to Nick's background of having grown up without parents, having no knowledge of his ancestry. I believe this is why Renard was trying to kill Nick's Aunt Marie before she could pass on any information to Nick to help guild him. Without the information Aunt Marie was able to give Nick on her death bed, Nick would have been completely lost. Nick's friendship with Monroe (and now Rosalie) was unexpected and something Renard could not have accounted for.. they will likely both be in jeopardy when/if Renard finds out about them. Renard is cleverly walking a fine line between trying to isolate Nick to better manipulate him (why he also tried to get rid of Hank) wihle also keeping Nick tied to the area/ his job (why he wanted to save Juliet).