MidGard
personally I feel this will either be his last or next to last bloodline. if he does get the opportunity to have another bloodline I would like to see him manage to make use of the illusion primogenitors bloodline just to kinda of bring it full circle to his original bloodlines also that should let him have a stronger advantage over the darkin trio
I think that he will keep going, since from what we saw with Noah, if this really is the last step and he is going to break through to origin realm, then the most he can get to is the same level as primogenitors, we have to remember that the final bosses are unigins, and the origin realm is the last realm in the human cultivation system, so it's he keeps going through more replacements even when he's at rpimo level till he's close to unigin lvl and breaks through or they find a new realm after origin realm because thats not enough