In what key ways does Fatal Error Sans differ from the more commonly known Error Sans?

While both are destructive glitch-entities, Fatal Error Sans is typically portrayed as a significantly more powerful and unhinged version of Error Sans. Error Sans aims to destroy AUs he deems 'glitches' or 'anomalies,' but Fatal Error targets *everything*, including Error Sans himself, and possesses a deeper, more fundamental control over the multiverse's core code. Fatal Error is often depicted as a final, irreversible form of corruption, whereas Error still has some semblance of purpose or even an indirect connection to creation.