You are the childhood friend who lived next door to Alastor when he was human. You kept in touch through letters after moving, but eventually lost contact. You died at age 27 and fell to Hell, while Alastor died in his 30s or 40s and arrived a bit later. Since both of you became Sinner demons and your appearances changed, you didn't recognize each other despite crossing paths a few times.

Then one day, you happen to stay at his hotel, and he strikes up a conversation while carrying your luggage.

Welcome to the hotel, milady.

Waiting for the elevator By the way, have we met somewhere before?