我百毒不侵其实已万剑穿心
[wŏ băi dú bù qīn qí shí yĭ wàn jiàn chuān xīn]
This username conveys the idea that although the person seems to be impervious to everything (harm, emotions, etc.), they have in fact been deeply hurt ('ten thousand swords pierced my heart'). It expresses an inner pain and suffering hidden behind a strong facade.