I bought two Puffadores to breed. But after getting them I noticed they have the same father. But in their lineage they dont register each other as brother and sister? In this game is there a restriction on breeding where you cant breed related monsters?

Ive played some pet games were you cant breed pets that are related to each other, and some games that dont restrict who you can breed with. So thats why I wanted to ask.

Yes, there are restrictions - sylesti cannot breed with direct relatives (i.e. siblings cannot breed with each other and parents cannot bred with offspring). Grandparents, cousins, etc are fine.

I believe the 'siblings' section only shows full siblings, and not half siblings. However, no sylesti related within a generation of eachother (siblings, half-siblings, parents, children) can breed.
So if they both show up in one of the parent's 'offspring' sections, they're a no-go for breeding together.

As Wander said, though, anything beyond that can breed.

Ok, thanks for the clarification! (The two Puffadores I have are still super cute, so I'll still keep them even if I can't breed) But I'll keep that in mind in the future when trying to set up breeding pairs!