Reported to be of one blood (7)
I believe the answer is:
related
'reported' is the definition.
(I've seen this before)
'be of one blood' is the wordplay.
I cannot quite see how this works, but
'be' could be 'relate' (relating is a kind of being) and 'relate' is located in the answer.
A single letter 'd' remains which might be clued in a way I don't see.
This may be the basis of clue (or it may be nonsense).
'to' acts as a link.
Can you help me to learn more?
(Other definitions for related that I've seen before include "Told (a story etc)" , "Family members must be" , "Akin, associated" , "Having common descent or origin" , "As siblings obviously are" .)