The Shadow of Sirius

After cursing Sirius Black three times never to return home again nor be able to speak to his wife, Remus Lupin, again unless she wishes him to speak to her first … or unless he wishes her to speak first instead, he has agreed not to do any harm to her directly nor indirectly either to herself or any member belonging to her household. If he feels Remus Lupin is putting his life in danger, he may curse him once more. If he feels someone else is putting his life in danger, he may curse them once more, but with certain conditions.

He cannot curse anyone else except for one person named Sirius Black (unless someone puts their life in danger) unless he feels Remus Lupin is putting her life in danger; then he may curse once more. This continues as a series of complex conditions and exceptions, including specific people such as Lizbeth Black, Harry Potter, Andromeda Tonks, James Potter, Lily Evans, Hermione Weasley, Severus Snape, Ronald Weasley, Neville Longbottom, Ginny Weasley, Bill Weasley, Charlie Weasley, Fleur Delacour, Nymphadora Tonks, Ginevra Weasley, Teddy Lupin, and Victoire Weasley.

In each case, the conditions stipulate that if he believes they are putting their lives in danger, he may curse them. Furthermore, if he finds himself in danger due to their actions, he may curse himself a certain number of times – increasing from once to thrice – in order to save himself from any danger. Ultimately, these convoluted conditions and protective measures seem to prioritize the safety of those listed, along with the self-preservation of Remus Lupin.