地久天荒c孤独终老c
[dì jiŭ tiān huāng c gū dú zhōng lăo c]
It means 'living alone forever'. The two 'c's could just add emphasis. There's an element of melancholy in this choice of username - expressing solitude over time, almost as if stating they've been alone since the dawn of creation and plan to continue being single indefinitely.