(Now, for some loose ends to be tied)

First;

Gilbert was working the late shift at the hospital again. He hadn't expected Antonio to show up with Francis that night. "Toni? I thought you and Franny hated each other?" Gilbert had puzzled.
"Events happened, and we forgave. Francis answered. "And, we have someone who wants to see you," Francis said. And in came Ludwig.
"Bruder?" Gilbert asked, tears filling his eyes.
"Bruder!" Ludwig said happily, and hugged his older brother.
"How are you alive after all these years?" Gilbert asked.
"I'm...not alive. I am Francis's guardian angel..." Ludwig explained, briefly. Luckily, Gilbert didn't care, as he was with his brother again. And they would never be separated again.

Then;

"Where do you think Arthur is?" Matthew asked his twin, one cloudy March day. Arthur had been gone for several days, as well as Francis (Really, they were just avoiding the bright sun).
"Don't know...I hope the limey's alright," Alfred replied.
"Who are you calling 'limey'?" Arthur scowled at the twins.
"Arthur!" They shouted in unison, and hugged him.
"Get off, you brats!" The Englishman tried to scowl.
"Mon amour, remember what we spoke about?" Francis chimed in, walking over.
"Ah, yes...boys, there's something important I must tell you," he said. Finally, the twins looked at him.
"What is it?"
"Francis and I...are actual vampires," he revealed, bearing his fangs. At first, Alfred laughed, but then saw they were real.
"Cool! C-can we be vampire's too?" Alfred asked.
Arthur looked at Francis, "I don't see why not," Francis said. So, that night, the twin brothers became part of the supernatural being family.

And finally;

'This is it,' Arthur thought as he fixed his tux. This was his last day as Arthur E. Kirkland. From this day forward, he would be Arthur E. Kirkland-Bonnefoy. 5 years had passed since the day they'd began officially dating, and Francis had popped the question.
Slowly, he walked down the aisle to his Frenchman. And from that day forward until the end of time, the couple was together, never to be apart, and life was brilliant.