Family Trees
Draw the bloodline.
Your characters already exist in your lore. The tree is built from them, so it can never disagree with them.
Built from your characters
You do not retype anyone. Pick the characters you already wrote up and connect them: parents, children, marriages, and the generations that follow.
Because the tree points at the same entries as everything else, opening a name in the tree opens the real character, with their dates, their events, and their links intact.
For the houses that matter
Successions, rival branches, and the cousin nobody remembers are exactly the details readers do remember. A tree makes them easy to keep straight while you write.