Of course Adam knew that Kaito Nakamura was Hiro's father. For him it had all happened when he met Kaito (remember, Adam is in the big death photo) and he had waited for 400 years. So when he met Kaito Nakamura, he knew that Hiro was soon to come. Trippy, isn't it, to think of having to wait for the kid you want to kill to be born.

I have no doubts that Adam wanted to kill Kaito himself. To get back at Hiro.

So this is a 400-year territory fight over a girl's heart!?! Bad Adam! Bad!