Go theme.

Only two rhymes over twenty-six lines? How boring.

So to you I plight my troth
In the night on bended knee,
O my love, my brooding Goth.

'Ere we met, I e'er was wroth;
Now I live in ecstasy;
So to you I plight my troth.

Through my heart you cut a swath
Like the Reaper's snickersnee,
O my love, my brooding Goth.

As the light attracts the moth,
Your bright darkness calls to me,
So to you I plight my troth.

Lust and Pride and Greed and Sloth,
All my sins I give for thee,
O my love, my brooding Goth.

Let a man in sable cloth
Bind our deaths eternally.
So to you I plight my troth,
O my love, my brooding Goth.

That wasn't hard. What's next, sestina?