FictionPack
Monochromatic Ursine
- Location
- Tennessee
- Pronouns
- He/Him
If you want an interpretationIf Wormtail had gotten the incantation wrong, then I could see problems occurring, but Harry saying "go ahead take it" would not make the ingredient any less the blood of an enemy, forcibly taken. In fact, an attempt to actively sabotage the ritual would only verify Harry's status as an enemy.
Blood of an enemy, forcibly taken, can be seen as connotations of conquest, of hatred, victory, pain, etc.
Blood of an enemy, willingly given, can have connotations of forgiveness, spite, mercy, subversion, etc.
You are correct that Harry will always be his enemy regardless. The important part in this theoretical is if the blood is taken or given.
We even have a canon example of this phenomenon in unicorns. Willingly given it can do wonderous things, but forcibly taken and it curses you.
Like mistaking salt for sugar when baking a cookie.(this analogy would probably work better with mixing up two different types of flour in a recipe)