一人独守寂寞凉心

Translating to 'Guarding Solitude Alone With A Cold Heart,' this screen name exudes deep solitude, isolation, and perhaps emotional withdrawal. It might hint at a person feeling misunderstood, having gone through something profoundly affecting, causing emotional scars that result in a seemingly 'cold' demeanor as they choose to isolate themselves from society, relationships, and even emotions to avoid getting hurt again.